Update syntax highlighters

Make sure these support all new keywords and tokens.

- [ ] https://github.com/gbdev/rgbds-live
- [x] https://github.com/DonaldHays/rgbds-vscode
- [ ] https://codeberg.org/ISSOtm/sublime-RGBDS
- [ ] https://codeberg.org/ISSOtm/gbz80-highlight

Also consider simplifying sublime-RGBDS to understand context *less*, and just highlight tokens instead of trying to mark whole lines as erroneous. (That way it won't be so forwards-incompatible with slightly new updates, but will keep on highlighting the keywords and tokens it recognizes.)

Start by comparing RGBDS's current keywords and tokens with the four listed highlighter projects: rgbds-live, rgbds-vscode, sublime-RGBDS, and gbz80-highlight. Update each unchecked integration to recognize the current syntax, and consider making sublime-RGBDS token-focused; done means all listed projects support the new syntax.

Written by the indexing model from the issue text.