add a knob to configure tree sitter timeout

[rcgoodfellow]

• adds syntax-timeout to languages configuration (not tied to any specific language)
• preserves existing half-second timeout as a default
• doing this because I have some very large KDL files I work with that take a bit longer than half a second to parse

[pascalkuthe]

I don't think thus make sense. A parsetime of 500ms was already quite a conservative timeout and will make editing/typing practically impossible. I would try to improve the parser for that particular language.

Longterm I think concerns likely this will be covered by async parsing and potentially dynamically adjusting the timeout based on edit size (shorter timeouts for small edits with the initial parse/big edits having maybe 1-2s timeouts)

[rcgoodfellow]

I would not describe the editing experience I have with this change as practically impossible, there is a bit of lag, but it's still very usable and the tradeoff is well worth it to have syntax highlighting. The half-second default is still preserved in this PR, it just gives folks that want to use helix to work with large files and have syntax highlighting a path to do so.

[rcgoodfellow]

This issue is also not specific to KDL. When I use Helix on large Rust files produced by code generators, I hit the half second timeout there as well. For those files, I'm oftentimes not editing them, so interactive editing speed is not as important, but syntax highlighting is important for reading code efficiently.