Problem: Sharing queries with upstream and Helix is difficult due to
different capture names.

Solution: Define and document a new set of standard captures that
matches tree-sitter "standard captures" (where defined) and is closer to
Helix' Atom-style nested groups.

This is a breaking change for colorschemes that defined highlights based
on the old captures. On the other hand, the default colorscheme now
defines links for all standard captures (not just those used in bundled
queries), improving the out-of-the-box experience.

* feat(treesitter): add injection language fallback

Problem: injection languages are often specified via aliases (e.g.,
filetype or in upper case), requiring custom directives.

Solution: include lookup logic (try as parser name, then filetype, then
lowercase) in LanguageTree itself and remove `#inject-language`
directive.

Co-authored-by: Lewis Russell <me@lewisr.dev>

* bundle split Markdown parser from https://github.com/MDeiml/tree-sitter-markdown
* add queries from https://github.com/nvim-treesitter/nvim-treesitter/tree/main
* upstream `#trim!` and `#inject-language!` directives

Co-authored-by: dundargoc <gocdundar@gmail.com>