CadQuery syntax highlighting

syntax highlighting is a very handy feature on many IDEs and is partially supported in CQ-editor (well done!).

It could be even better if CadQuery's builtin functions (`Workplane`, `box`, `center`, `hole`, etc. - basically all what is listed in the [CadQuery Class reference](https://cadquery.readthedocs.io/en/latest/classreference.html)) were rendered with a different color, or maybe with several colors (but not too many), in order to distinguish Core classes, Selector Classes, etc.