- also unset b:ts_highlight on stop()

Fixes: #21836

fix(treesitter): check buffer is loaded when restoring options

Also restore spelloptions

Fixes #21416

* add type annotations to code
* clean up and expand static documentation
* consistent use of tags for static and generated docs

- Added 'spell' option to extmarks:

  Extmarks with this set will have the region spellchecked.

- Added 'noplainbuffer' option to 'spelloptions':

  This is used to tell Neovim not to spellcheck the buffer. The old
  behaviour was to spell check the whole buffer unless :syntax was set.

- Added spelling support to the treesitter highlighter:

  @spell captures in highlights.scm are used to define regions which
  should be spell checked.

- Added support for navigating spell errors for extmarks:

  Works for both ephemeral and static extmarks

- Added '_on_spell_nav' callback for decoration providers:

  Since ephemeral callbacks are only drawn for the visible screen,
  providers must implement this callback to instruct Neovim which
  regions in the buffer need can be spell checked.

  The callback takes a start position and an end position.

  Note: this callback is subject to change hence the _ prefix.

- Added spell captures for built-in support languages

Co-authored-by: Lewis Russell <lewis6991@gmail.com>
Co-authored-by: Björn Linse <bjorn.linse@gmail.com>

This removes the support for defining links via
vim.treesitter.highlighter.hl_map (never documented, but plugins did
anyway), or the uppercase-only `@FooGroup.Bar` to `FooGroup` rule.

The fallback is now strictly `@foo.bar.lang` to `@foo.bar` to `@foo`,
and casing is irrelevant (as it already was outside of treesitter)

For compatibility, define default links to builting syntax groups
as defined by pre-existing color schemes

Signed-off-by: Raphael <glephunter@gmail.com>

* reformat Lua runtime to make lint CI pass
* reduce max line length to 100