Problem: `migrate_integrations` warned about old top-level keys even
when the user had already adopted `integrations`, which would be noisy
for configs that happen to have both.
Solution: only emit `vim.deprecate` and migrate values when
`opts.integrations` was not explicitly provided. When it is, old
top-level keys are silently stripped.
Problem: integration keys (`fugitive`, `neogit`, `gitsigns`, `committia`,
`telescope`) live at the top level of `vim.g.diffs`, cluttering the
config alongside unrelated options like `highlights` and `conflict`.
Solution: move them under `vim.g.diffs.integrations.*`. Old top-level
keys are migrated automatically with a `vim.deprecate` warning targeting
v0.3.2. `compute_filetypes` and `plugin/diffs.lua` fall back to legacy
keys for pre-`init()` callers.
Closes#169.
## Problem
Telescope never sets `filetype=diff` on preview buffers — it calls
`vim.treesitter.start(bufnr, "diff")` directly, so diffs.nvim's
`FileType` autocmd never fires.
## Solution
Add a `telescope` config toggle (same pattern as
neogit/gitsigns/committia) and a `User TelescopePreviewerLoaded` autocmd
that calls `attach()` on the preview buffer. Disabled by default; enable
with `telescope = true`.
Also adds a `diffs-telescope` vimdoc section documenting the integration
and the upstream first-line preview bug
(nvim-telescope/telescope.nvim#3626).
Includes committia.vim integration from `feat/committia`.
## Problem
committia.vim's diff pane (`ft=git`, buffer name `__committia_diff__`)
is rejected by the `ft=git` guard in the `FileType` callback, preventing
diffs.nvim from highlighting it.
## Solution
Add a `committia` config toggle following the same pattern as
`neogit`/`gitsigns`. When enabled, the `ft=git` guard also allows
committia's `__committia_diff__` buffer through.
Closes#161
## Problem
gitsigns' `:Gitsigns blame_line` popup shows flat
`GitSignsAddPreview`/`GitSignsDeletePreview` line highlights with basic
word-level inline diffs, but no treesitter syntax or diffs.nvim's
character-level intra-line highlighting.
## Solution
Add `lua/diffs/gitsigns.lua` which patches gitsigns' `Popup.create` and
`Popup.update` to intercept blame popups. Parses `Hunk N of M` sections
from the popup buffer, clears gitsigns' own `gitsigns_popup` namespace
on the diff region, and applies `highlight_hunk` with manual
`@diff.plus`/`@diff.minus` prefix extmarks. Uses a separate
`diffs-gitsigns` namespace to avoid colliding with the main decoration
provider.
Enabled via `vim.g.diffs = { gitsigns = true }`. Wired in
`plugin/diffs.lua` with a `User GitAttach` lazy-load retry for when
gitsigns loads after diffs.nvim. Config plumbing adds
`get_highlight_opts()` as a public getter, replacing the
`debug.getupvalue` hack used by the standalone `blame_hl.nvim` plugin.
Closes#155.
## Problem
Neovim 0.11+ deprecated the table-based `vim.validate({...})` form.
Every
plugin load produces 5 deprecation warnings pointing at `init.lua`
config
validation.
## Solution
Convert all `vim.validate` calls in `init()` to the new positional
`vim.validate(name, value, validator, optional_or_msg)` form. No
behavioral
change — identical validation logic, just the calling convention.
## Problem
Highlight group fallbacks in `compute_highlight_groups` were hardcoded
to
catppuccin mocha colors, producing wrong results for any other
colorscheme
when `Normal.bg` is nil. This happens on transparent terminals or when
the
colorscheme loads after the first diff buffer opens.
## Solution
Replace hardcoded fallbacks with `vim.o.background`-aware neutral
values.
When `Normal.bg` is still absent after initial computation, schedule a
single
deferred retry via `vim.schedule` that recomputes and invalidates all
attached
buffer caches. Document the load-order requirement in the setup section.
## Problem
`highlights.context.enabled` and `highlights.context.lines` were
defined, validated, and range-checked but never read during
highlighting. Hunks inside incomplete constructs (e.g., a table literal
or function body whose opening is beyond the hunk's own context lines)
parsed incorrectly because treesitter had no surrounding code.
## Solution
`compute_hunk_context` in `init.lua` reads the working tree file using
the hunk's `@@ +start,count @@` line numbers to collect up to `lines`
(default 25) surrounding code lines in each direction. Files are read
once via `io.open` and cached across hunks in the same file.
`highlight_treesitter` in `highlight.lua` accepts an optional context
parameter that prepends/appends context lines to the parse string and
offsets capture rows by the prefix count, so extmarks only land on
actual hunk lines. Wired through `highlight_hunk` for the two
code-language treesitter calls (not headers, not `highlight_text`, not
vim syntax).
Closes#148.
## Problem
Languages without a treesitter parser (COBOL, Fortran, etc.) got no
syntax highlighting because \`highlights.vim.enabled\` defaulted to
\`false\`.
## Solution
Flip the default to \`true\`. The vim syntax path is already deferred
via \`vim.schedule\` so it never blocks the first paint. \`max_lines =
200\` stays unchanged — appropriate given the ~30x slower per-hunk cost
vs treesitter.
## Problem
Email-quoted diffs (`> diff --git ...`, `> @@ ...`) from git-send-email
/ email reply workflows produce 0 hunks because the parser matches
patterns against raw lines containing `> ` quote prefixes. Closes#141.
## Solution
Strip the `> ` quote prefix before pattern matching in the parser. Store
`quote_width` on each hunk. In `highlight.lua`, offset all extmark
column positions by `qw` and expand `pw > 1` guards to `qw > 0 or pw >
1` for DiffsClear suppression. Clamp body prefix DiffsClear `end_col` to
the actual buffer line byte length for bare `>` lines (1-byte buffer
lines where `end_col = pw + qw` would exceed bounds and cause
`nvim_buf_set_extmark` to silently fail inside `pcall`).
15 new specs covering parser detection, stripping, false-positive
rejection, and highlight column offsets including the bare `>` clamp
edge case.
## Problem
diffs.nvim blanked `NeogitDiffContextHighlight` globally on attach and
on `ColorScheme` to work around Neogit's `ViewContext` decoration
provider overriding `DiffsAdd`/`DiffsDelete` line backgrounds with
`NeogitDiffContextHighlight` at priority 200.
## Solution
Remove the `override_neogit_context_highlights` workaround.
NeogitOrg/neogit#1907 moves the `neogit_disable_hunk_highlight` check
inside ViewContext's per-line loop, so non-cursor lines skip
`add_line_highlight` entirely.
`vim.b[bufnr].neogit_disable_hunk_highlight = true` (set on attach) is
sufficient.
Closes#135
## Problem
Two-pass rendering (Pass 1: backgrounds + intra-line; Pass 2:
treesitter) caused Pass 2 to re-apply all extmarks that Pass 1 already
set, doubling the extmark count on affected lines.
## Solution
Add `syntax_only` mode to `highlight_hunk`. When `syntax_only = true`,
only treesitter syntax and content `DiffsClear` extmarks are applied —
backgrounds, intra-line, prefix clears, and per-char prefix highlights
are skipped. Pass 2 now uses `syntax_only = true` and no longer calls
`nvim_buf_clear_namespace`, so Pass 1's extmarks persist while Pass 2
layers syntax on top.
Closes#143
## Problem
`highlight_hunk` applied DiffsClear extmarks across 5 scattered sites
with
ad-hoc column arithmetic. This fragmentation produced the 1-column
DiffsClear
gap on email-quoted body context lines (#142 issue 1). A redundant
`highlight_hunk_vim_syntax` function duplicated the inline vim syntax
path,
and the deferred pass in init.lua double-called it, creating duplicate
scratch
buffers and extmarks.
## Solution
Reorganize `highlight_hunk` into two clean phases:
- **Phase 1** — multi-line syntax computation (treesitter, vim syntax,
diff
grammar, header context text). Sets syntax extmarks only, no DiffsClear.
- **Phase 2** — per-line chrome (DiffsClear, backgrounds, gutter,
overlays,
intra-line). All non-syntax extmarks consolidated in one pass.
Hoist `new_code` to function scope (needed by `highlight_text` outside
the
`use_ts` block). Hoist `at_raw_line` so Phase 1d and Phase 2b share one
`nvim_buf_get_lines` call.
Delete `highlight_hunk_vim_syntax` (redundant with inline path). Remove
the
double-call from the deferred pass in init.lua.
Extend body prefix DiffsClear `end_col` from `qw` to `pw + qw`, fixing
the
1-column gap where native treesitter background bled through on context
lines
in email-quoted diffs (#142 issue 1).
### Email-quoted diff support
The parser now strips `> ` (and `>> `, etc.) email quote prefixes before
pattern matching, enabling syntax highlighting for diffs embedded in
email
replies and `git-send-email` / sourcehut-style patch review threads.
Each hunk stores `quote_width` so the highlight pipeline can apply
`DiffsClear` at the correct column offsets to suppress native treesitter
on quoted regions.
Closes#141
### #142 status after this PR
| Sub-issue | Status |
|-----------|--------|
| 1. Col gap on context lines | Fixed |
| 2. Bare `>` context lines | Improved, edge case remains |
| 3. Diff prefix marker fg | Not addressed (follow-up) |
## Problem
Repeatedly toggling `=` in fugitive left green gutter
(`number_hl_group`)
extmarks on lines between sections. When fugitive collapses a diff
section,
Neovim compresses extmarks from deleted lines onto the next surviving
line
(the `M ...` file entry). Two issues prevented cleanup:
1. `carry_forward_highlighted` returned `{}` (truthy in Lua) when zero
hunks
matched, so `pending_clear` stayed `false` and the compressed extmarks
were never cleared.
2. The `nvim_buf_clear_namespace` call in `on_buf`'s `pending_clear`
path was
removed in 2feb8a8, so even when `pending_clear` was `true` the extmarks
survived.
## Solution
Return `nil` from `carry_forward_highlighted` when no hunks were carried
forward (`next(highlighted) == nil`), so `pending_clear` is correctly
set to
`true`. Restore `nvim_buf_clear_namespace` in `on_buf`'s `pending_clear`
block. Add `process_pending_clear` test helper and spec coverage.
## Problem
Toggling large diffs via fugitive's `=` caused the top of the buffer to
re-render and glitch. `ensure_cache` always created a new cache entry
with
`pending_clear=true` and `highlighted={}`, forcing `on_win` to clear and
re-highlight every visible hunk — including stable ones above the toggle
point that never changed.
## Solution
On reparse, compare old and new hunk lists using a prefix + suffix
matching
strategy. Hunks that match (same filename, line count, and sampled
content)
carry forward their `highlighted` state so `on_win` skips them.
Comparison
is O(1) per hunk. Only runs when the old entry had
`pending_clear=false`;
`invalidate_cache`/`ColorScheme` paths still force full re-highlight.
Closes#131
## Problem
diffs.nvim was blanking 18 Neogit highlight groups globally on attach to
prevent Neogit's `line_hl_group` fg from stomping treesitter syntax. It
also fell back to `getcwd()` plus a subprocess call for repo root
detection on Neogit buffers, and had no mechanism to refresh the hunk
cache when Neogit lazy-loaded new diff sections.
## Solution
Adopts three APIs introduced in NeogitOrg/neogit#1897:
- Sets `vim.b.neogit_disable_hunk_highlight = true` on the Neogit buffer
at attach time. Neogit's `HunkLine` renderer skips all its own highlight
logic when this is set, replacing the need to blank 18 hl groups
globally and the associated ColorScheme re-application.
- Reads `vim.b.neogit_git_dir` in `get_repo_root()` as a reliable
fallback between the existing `b:git_dir` check and the `getcwd()`
subprocess path.
- Registers a buffer-local `User NeogitDiffLoaded` autocmd on attach
that calls `M.refresh()` when Neogit lazy-loads a new diff section,
keeping the hunk cache in sync.
Closes#128
## Problem
The default conflict navigation keymaps `]x`/`[x` are non-standard. Vim
natively uses `]c`/`[c` for diff navigation, so the same keys are far
more
intuitive for conflict jumping.
## Solution
Change the defaults for `conflict.keymaps.next` and
`conflict.keymaps.prev`
to `]c` and `[c`. This is a breaking change for users relying on the
previous
defaults without explicit configuration.
## Problem
Git diff metadata lines like "new file mode 100644" and "deleted file
mode 100644" matched the neogit "new file" and "deleted" filename
patterns in the parser, corrupting the current filename and breaking
syntax highlighting for subsequent hunks.
Closes#120
## Solution
Add negative guards so "new file mode" and "deleted file mode" lines
are skipped before the neogit filename capture runs. The guard must
evaluate before the capture due to Lua's and/or short-circuit semantics
— otherwise the and-operator returns true instead of the captured
string.
Added 16 parser tests covering all neogit filename patterns, all git
diff extended header lines that could collide, and integration scenarios
with mixed neogit status + diff metadata buffers.
## Problem
Users had to pass `enabled = true` or `enabled = false` inside
fugitive/neogit config tables, which was redundant — table presence
already implied the integration should be active.
## Solution
Remove the `enabled` field from the public API. Table presence now
implies enabled, `false` disables, `true` expands to sub-defaults.
The `enabled` field is still accepted for backward compatibility.
Added 20 `compute_filetypes` tests covering all config shapes (true,
false, table, nil, backward-compat enabled field). Updated docs
and type annotations.
## Problem
The neogit commit (3d640c2) switched line background extmarks from
`hl_group`+`hl_eol` to `line_hl_group`. Due to [neovim#31151][1],
`line_hl_group` bg overrides `hl_group` bg regardless of extmark
priority. This made `DiffsAddText`/`DiffsDeleteText` intra-line
highlights invisible beneath line backgrounds — the extmarks were
placed correctly but Neovim rendered the line bg on top.
[1]: https://github.com/neovim/neovim/issues/31151
## Solution
Revert line backgrounds to `hl_group`+`hl_eol` where priority stacking
works correctly. Keep `number_hl_group` in a separate point extmark to
prevent gutter color bleeding to adjacent lines. The Neogit highlight
override (clearing their groups to `{}`) is independent and unaffected.
## Problem
Commit 0f27488 changed fugitive and neogit integrations from enabled by
default
to disabled by default. Users who never explicitly set these keys in
their config
saw no deprecation notice and silently lost integration support. The
existing
deprecation warning only fires for the old `filetypes` key, missing the
far more
common case of users who had no explicit config at all.
## Solution
Add an ephemeral migration check in `init()` that emits a `vim.notify`
warning
at WARN level when `fugitive`, `neogit`, and `diff` (via
`extra_filetypes`) are
all absent from the user's config. This covers the gap between the old
`filetypes`
deprecation and users who relied on implicit defaults. To be removed in
0.3.0.
## TODO
1. docs (vimdoc + readme) - this is a non-trivial feature
2. push luarocks version
## Problem
diffs.nvim only activates on `fugitive`, `git`, and `gitcommit`
filetypes.
Neogit uses its own custom filetypes (`NeogitStatus`,
`NeogitCommitView`,
`NeogitDiffView`) and doesn't set `b:git_dir`, so the plugin never
attaches
and repo root resolution fails for filetype detection within diff hunks.
## Solution
Two changes:
1. **`lua/diffs/init.lua`** — Add the three Neogit filetypes to the
default
`filetypes` list. The `FileType` autocmd in `plugin/diffs.lua` already
handles them correctly since the `is_fugitive_buffer` guard only applies
to the `git` filetype.
2. **`lua/diffs/parser.lua`** — Add a CWD-based fallback in
`get_repo_root()`.
After the existing `b:diffs_repo_root` and `b:git_dir` checks, fall back
to
`vim.fn.getcwd()` via `git.get_repo_root()` (already cached). Without
this,
the parser can't resolve filetypes for files in Neogit buffers.
Neogit's expanded diffs use standard unified diff format, so the parser
handles
them without modification.
Closes#110.
## Problem
Fugitive shows combined diffs (`@@@` headers, 2-character prefixes like
`++`, ` +`, `+ `) for unmerged (`UU`) files. The parser and highlight
pipeline assumed unified diff format (`@@`, 1-char prefix), causing:
- Prefix concealment only hiding 1 of 2 prefix chars
- Missing background colors on ` +` and `+ ` lines (first char is space
→ misclassified as context)
- No treesitter highlights (extra prefix char poisoned code arrays)
- `U` file header not recognized by parser (missing from filename
pattern)
## Solution
Detect prefix width from leading `@` count in hunk headers (`@@` → 1,
`@@@` → 2). Propagate `prefix_width` through the pipeline:
- **Parser**: new `prefix_width` field on `diffs.Hunk`, `U` added to
filename pattern, combined diff range extraction
- **Highlight**: prefix stripping, `col_offset`, concealment width, and
line classification all use `prefix_width`
- **Intra-line**: skipped for combined diffs (`prefix_width > 1`) since
2-char prefix semantics don't produce meaningful change groups
## Problem
Three minor issues remain before the v0.2.0 release:
1. Git quotes filenames containing spaces, unicode, or special
characters
in the fugitive status buffer. `parse_file_line` passed the quotes
through verbatim, causing file-not-found errors on diff operations.
2. Navigation wrap-around in both conflict and merge modules was silent,
giving no indication when jumping past the last/first item back to the
beginning/end.
3. `resolved_hunks` and `(resolved)` virtual text in the merge module
persisted across buffer re-reads, showing stale markers for hunks that
were no longer resolved.
## Solution
1. Add an `unquote()` helper to fugitive.lua that strips surrounding
quotes and unescapes `\\`, `\"`, `\n`, `\t`, and octal `\NNN`
sequences. Applied to both return paths in `parse_file_line`.
2. Add `vim.notify` before the wrap-around jump in all four navigation
functions (`goto_next`/`goto_prev` in conflict.lua and merge.lua).
3. Clear `resolved_hunks[bufnr]` and the merge namespace at the top of
`setup_keymaps` so each buffer init starts fresh.
Closes#66
## Problem
Conflict resolution virtual text only showed plain "current" /
"incoming"
labels with no keymap hints. Users had no way to discover available
resolution keymaps without reading docs.
## Solution
Default virtual text labels now include keymap hints: `(current — doo)`
and
`(incoming — dot)`. A new `format_virtual_text` config option lets users
customize or hide labels entirely. A new `show_actions` option (off by
default) renders a codelens-style action line above each `<<<<<<<`
marker
listing all enabled resolution keymaps. Merge diff views also gain hunk
hints on `@@` header lines showing available keymaps.
New config fields: `conflict.format_virtual_text` (function|nil),
`conflict.show_actions` (boolean). New highlight group:
`DiffsConflictActions`.
## Problem
`get_repo_root()` shells out to `git rev-parse` on every call, causing
4-6
redundant subprocesses per `gdiff_file()` invocation. Three other minor
issues: `highlight_vim_syntax()` leaks a scratch buffer if
`nvim_buf_call`
errors, `lib.ensure()` silently drops callbacks during download so hunks
highlighted mid-download permanently miss intra-line highlights, and the
debounce timer callback can operate on a deleted buffer.
## Solution
Cache `get_repo_root()` results by parent directory — repo roots don't
change within a session. Wrap `nvim_buf_call` and `nvim_buf_delete` in
pcall so the scratch buffer is always cleaned up. Replace the early
`callback(nil)` in `lib.ensure()` with a pending callback queue that
fires
once the download completes. Guard the debounce timer callback with
`nvim_buf_is_valid`.
## Problem
Pressing `du` on a `UU` (unmerged) file in the fugitive status buffer
had no
effect. There was no way to see a proper ours-vs-theirs diff with syntax
highlighting and intra-line changes, or to resolve conflicts from within
a
unified diff view.
Additionally, pressing `du` on a section header containing only unmerged
files
showed "no changes in section" because `git diff` produces combined
(`diff --cc`)
output for unmerged files, which was stripped entirely.
## Solution
Fetch `:2:` (ours) and `:3:` (theirs) from the git index and generate a
standard
unified diff. The existing highlight pipeline (treesitter + intra-line)
applies
automatically. Resolution keymaps (`doo`/`dot`/`dob`/`don`) on hunks in
the diff
view write changes back to the working file's conflict markers.
Navigation
(`]x`/`[x`) jumps between unresolved conflict hunks.
For section diffs, combined diff entries are now replaced with generated
ours-vs-theirs unified diffs instead of being stripped.
Works for merge, cherry-pick, and rebase conflicts — git populates
`:2:`/`:3:`
the same way for all three.
Closes#61
Problem: after resolving all conflicts, vim.diagnostic.enable(true)
restored diagnostics that were cached while markers were present,
showing errors like "unexpected token end" on clean code.
Solution: call vim.diagnostic.reset() before re-enabling to flush
stale results and let the LSP re-analyze the resolved buffer.
Problem: resolving the last conflict called M.detach(), which cleared
attached_buffers[bufnr]. The TextChanged callback then returned true,
permanently deleting the autocmd. Undo restored conflict markers but
nothing re-highlighted or re-suppressed diagnostics.
Solution: inline the cleanup in refresh() instead of calling detach().
Keep attached_buffers set so the autocmd survives. Re-suppress
diagnostics when conflicts reappear after undo.
Problem: virtual text showed generic "current"/"incoming" labels with
no indication of which branch each side came from.
Solution: extract the branch name from the marker line itself
(e.g. <<<<<<< HEAD, >>>>>>> feature) and display as
"HEAD (current)" / "feature (incoming)".
Problem: LuaLS reports missing-fields errors because the parser builds
ConflictRegion tables incrementally, but the variable is typed as
diffs.ConflictRegion? which expects all required fields at construction.
Solution: type the work-in-progress variable as table? and cast to
diffs.ConflictRegion on insertion into the results array.
Problem: lua-language-server reports duplicate @class definitions for
ConflictKeymaps and ConflictConfig (defined in both init.lua and
conflict.lua), and inject-field errors for the untyped parser table.
Solution: remove duplicate @class annotations from conflict.lua
(init.lua is the canonical source), and annotate the parser's current
variable as diffs.ConflictRegion? so LuaLS knows its shape.
Problem: when git hits a merge conflict, users stare at raw <<<<<<<
markers with broken treesitter and noisy LSP diagnostics. Existing
solutions (git-conflict.nvim) use their own highlighting rather than
integrating with diffs.nvim's color blending pipeline.
Solution: add conflict.lua module that detects <<<<<<</=======/>>>>>>>
markers (with diff3 ||||||| support), highlights ours/theirs/base
regions with blended DiffsConflict* highlight groups, provides
resolution keymaps (doo/dot/dob/don) and navigation (]x/[x),
suppresses diagnostics while markers are present, and auto-detaches
when all conflicts are resolved. Fires DiffsConflictResolved user
event on last resolution.
Problem: diffs:// buffers could trigger spurious LSP diagnostics,
opening multiple diffs from fugitive created redundant splits, and
there was no quick way to close diff windows.
Solution: disable diagnostics on diff buffers, reuse existing
diffs:// windows in the tabpage instead of creating new splits,
and add a buffer-local q keymap to close diff windows.
Problem: users had no config-level way to override computed highlight
groups and had to call nvim_set_hl externally.
Solution: add highlights.overrides table that maps group names to
highlight definitions. Overrides are applied after all computed groups
without default = true, so they always win over both computed defaults
and colorscheme definitions.
Problem: the character-level blend intensity was hardcoded to 0.6,
giving users no way to tune how strongly changed characters stand out
from the line-level background.
Solution: add highlights.blend_alpha config option (number, 0-1,
default 0.6) with type validation and range check.
Problem: DiffsDiff* highlight groups lacked default = true, making them
impossible for colorschemes to override, inconsistent with the fugitive
unified diff groups which already had it.
Solution: add default = true to all four DiffsDiffAdd, DiffsDiffDelete,
DiffsDiffChange, and DiffsDiffText nvim_set_hl calls.
Problem: DiffsAddNr/DiffsDeleteNr used raw diffAdded/diffRemoved
foreground and the word-level blended background, instead of matching
the line-level and character-level highlight groups.
Solution: set gutter bg to the line-level blend (DiffsAdd/DiffsDelete)
and fg to the character-level blend (DiffsAddText/DiffsDeleteText).
Problem: word-level diff highlights were too intense at 70% alpha, and
line number backgrounds used the line-level blend instead of matching
the word-level highlights.
Solution: reduce DiffsAddText/DiffsDeleteText blend alpha from 0.7 to
0.6 and use the same blended background for DiffsAddNr/DiffsDeleteNr.
Problem: the header context string (e.g. "function M.setup()") was
parsed in isolation by treesitter, which couldn't recognize "function"
as @keyword.function because the snippet is an incomplete definition
with no body or "end".
Solution: append the already-built new_code lines as trailing context
when parsing the header string, giving treesitter a complete function
definition. Filter captures to row 0 only so body-line captures don't
produce extmarks on the header line.
Problem: hl_eol requires a multiline extmark to extend the background
past end-of-line. The extmark used end_col = line_len on the same
row, so it was single-line and hl_eol was effectively a no-op.
Solution: replace end_col with end_row targeting the next line so
the extmark is multiline and hl_eol takes effect. Split
number_hl_group into a separate extmark to prevent it bleeding to
adjacent lines.
Problem: highlight_treesitter only iterated captures from the base
language tree (trees[1]:root()). When code contained injected
languages (e.g. VimL inside vim.cmd()), those captures were never
read, so injected code got no syntax highlighting in diffs.
Solution: pass true to parse() to trigger injection discovery, then
use parser_obj:for_each_tree() to iterate all trees including
injected ones. Each tree gets its own highlights query looked up by
ltree:lang(), and @spell/@nospell captures are filtered out.
