Tree-sitter injections

An injection query identifies regions of a host language that should be highlighted with another grammar. Configure injection_query and injected_languages on a language to enable this independently of any built-in language integration.

For example, this workspace configuration treats Rust raw-string contents as JSON:

{
  "languages": {
    "rust": {
      "injection_query": "((raw_string_literal (string_content) @injection.content) (#set! injection.language \"json\"))",
      "injected_languages": ["json"]
    }
  }
}

The query marks embedded text with @injection.content and supplies its language using #set! injection.language or an @injection.language capture. injected_languages lists the language configurations to load for highlighting. Unknown language names are skipped.

Syntax-node, syntax-token, and top-node selections use the embedded tree inside each captured region. Selections crossing a region boundary use the host tree. Trees are refreshed after edits and language changes. Each content capture is parsed independently; combined and recursively nested injections are not yet supported for structural navigation.