Problem:
Treesitter highlighting is slow for large files with lots of injections.
Solution:
Only parse injections we are going to render during a redraw cycle.
---
- `LanguageTree:parse()` will no longer parse injections by default and
now requires an explicit range argument to be passed.
- `TSHighlighter` now parses injections incrementally during on_win
callbacks for the line range being rendered.
- Plugins which require certain injections to be parsed must run
`parser:parse({ start_row, end_row })` before using the tree.
2ca076e45f
