Extended highlight queries

[omentic]

Hi alaviss: I just finished porting Helix's old highlight queries to your grammar. You might be interested in them, they're about 150 lines longer but highlight significantly more accurately. I'd make a PR, but I'm not actually sure what scope standard your highlights are based off of...

They're available here: https://github.com/omentic/helix/blob/master/runtime/queries/nim/highlights.scm