Problem: if `Normal.bg` is nil when `compute_highlight_groups` first runs
(colorscheme not yet loaded), the neutral fallbacks are baked in and never
corrected — the `ColorScheme` autocmd only fires for explicit `:colorscheme`
calls, which may come too late for some plugin manager configurations.
Solution: when `Normal.bg` is absent, schedule a single deferred retry via
`vim.schedule` that recomputes all highlight groups and invalidates attached
buffer caches once the event loop settles. Also document the load-order
requirement and the retry behaviour in the highlight groups section of the
vimdoc.
Barrett Ruth
d1f7acde8e
