* inject language based on file extension
Nodes can now be captured with "injection.filename". If this capture
contains a valid file extension known to Helix, then the content will
be highlighted as that language.
* inject language by shebang
Nodes can now be captured with "injection.shebang". If this capture
contains a valid shebang line known to Helix, then the content will
be highlighted as the language the shebang calls for.
* add documentation for language injection
* nix: fix highlights
The `@` is now highlighted properly on either side of the function arg.
Also, extending the phases with `buildPhase = prev.buildPhase + ''''`
is now highlighted properly.
Fix highlighting of `''$` style escapes (requires tree-sitter-nix bump)
Fix `inherit` highlighting.
* simplify injection_for_match
Split out injection pair logic into its own method to make the overall
flow easier to follow.
Also transform the top-level function into a method on a
HighlightConfiguration.
* markdown: add shebang injection query
HTML nodes should be combined injections in the markdown block
grammar. When nodes are together the highlighting works properly but
when there is markdown content between HTML nodes like in a `<details>`
tag, the highlighting of the closing tag breaks since tree-sitter-html
looks for opening and closing tags.
