Add some way to override the existing queries bundled with the package

[mohkale]

I recently upgraded tree-sitter-langs (after a few months) and I've noticed quite a lot of the syntax highlighting has been improved in places. However in some cases I also find it kind of overbearing.

For example in shell script mode command flags are highlighted as constants, variables are also properties, commands invocations are function calls, etc.

While it would be easy enough to modify the queries bundled with this repo, there's no easy way to persist those changes into my emacs dotfiles without maintaining a fork of this project. I think it'd be nice if tree-sitter-langs had a local directory variable users can set and if a query is defined there then it uses that query instead of the one bundled with this repo. Thoughts?

[ubolonton]

I think such a mechanism would be useful. I don't have time to work on in at the moment, though.