language: Reset pooled tree-sitter parsers after cancellation (#55866)

It seems new cancellation behavior in tree-sitter caused at least one
issue for a user.
Attempting to proactively reset before any parser use to make sure
things are clean.

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- N/A
8e4c329ee3Ben Brandt committed on 5/6/2026, 5:01:49 PM· committed by GitHubparentc83f3fe
1 file changedLine totals unavailable