Implement the LanguageTree structure to enable language injection.
This is done be removing the old Parser metatable and replacing by the
new structure, with the same API (almost).
Some noticeable differences :
- `parser:parse()` now returns a table of trees
- There is no incremental parsing for child (injected) languages
Co-authored-by: Thomas Vigouroux <tomvig38@gmail.com>
- Describe query components (capture, match, pattern). Not
well-described in tree-sitter documentation.
- Describe Query() object. Not actually described anywhere in
documenation.
