Add support for Djot

[sudanchapagain]

Could support for .djot & .dj be added? At the very least the syntax highlighting.

Djot site

[TornaxO7]

You can meanwhile add the support manually in our config (see the entry grammar in the table).

[mmibbetson]

Per #3020 and this comment on #3019, the queries in the tree-sitter-djot repository won't work.

I've written/adapted the highlights and injections for tree-sitter-djot to fit the current helix precedence order and the appropriate highlighting scopes. I'm currently getting the appropriate portion of the language.toml ready.

It looks like there is going to be a significant change to the tree-sitter-djot grammar in the future, so I'll have to come back to this and adapt. But for now, I'm hoping to get a pull request ready for the current version by the end of the week.

[mmibbetson]

If you're curious about what the highlights are looking like in Helix, I've provided some screenshots in this comment on the PR.