refactor(treesitter): drop `LanguageTree._has_regions` #32274

This simplifies some logic in `languagetree.lua`, removing the need for
`_has_regions`, and removing side effects in `:included_regions()`.

Before:
- Edit is made which sets `_regions = nil`
- Upon the next call to `included_regions()` (usually right after we
  marked `_regions` as `nil` due to an `_iter_regions()` call), if
  `_regions` is nil, we repopulate the table (as long as the tree
  actually has regions)

After:
- Edit is made which resets `_regions` if it exists
- `included_regions()` no longer needs to perform this logic itself, and
  also no longer needs to read a `_has_regions` variable

0 files changed, 0 insertions, 0 deletions