I've noticed that some of the themes in helix are using undocumented highlight selectors. Well that's no surprise, these are comming from highlight.scm files in tree-sitter grammars, while the least terrible reference to these classes seems to be https://docs.helix-editor.com/themes.html
We can do better. So first I'm going to just start collecting notes from existing grammars. Two main things will be here: references to "standard" classes, and also guidance for how to change "non-standard" classes.
Current doc source: https://github.com/helix-editor/helix/blob/master/book/src/themes.md
attribute
- Class attributes, HTML tag attributes