Previously, hunks were discarded entirely if vim.filetype.match()
returned nil. This meant files with unrecognized extensions got no
highlighting at all - not even the basic green/red backgrounds for
added/deleted lines.
Remove the (current_lang or current_ft) condition from flush_hunk()
so all hunks are collected. highlight_hunk() already handles the
case where ft/lang are nil by skipping syntax highlighting but still
applying background colors.
Co-authored-by: phanen <phanen@qq.com>
Apply treesitter highlighting to diff metadata lines (diff --git, index,
---, +++) using the diff language parser. Header info is attached only
to the first hunk of each file to avoid duplicate highlighting.
Based on PR #52 by @phanen with fixes:
- header_lines now only contains diff metadata, not hunk content
- header info attached only to first hunk per file
- removed arbitrary hunk count restriction
