ToDo: add RgbArg

[NoSloppy]

There's no way to click a button to sub in RgbArg for a COLOR as of now.

[profezzorn]

At least in some cases, the "Argify" button will do just that.

[NoSloppy]

Yeah I don't remember what I was doing when this was submitted. Probably meant something along the lines of making it aware that a color is substitutable for the entire argument the same way other things are swappable. While Argify applies to the whole style, this would allow individual swapping.