Add slint

[powpingdone]

Slint has a different repo owner than tree sitter's, otherwise it's the standard fare.

[jcs090218]

Adding only the submodule is probably not very helpful. 🤔 You can use https://github.com/emacs-tree-sitter/tree-sitter-langs/pull/1000/files as the reference. :)

[powpingdone]

Unfortunately there isn't a "slint mode" yet as an emacs plugin. Do you write the scm files manually?

[jcs090218]

I usually copied from neo-vim-treesitter repo or the main tree-sitter- repo from the upstream. 🤔

[powpingdone]

Alright, added the SCM stuffs, updated the gh workflow and changelog

[powpingdone]

Bump, dunno if you saw I threw that commit in.

[jcs090218]

Thank you!