Add spaces to color parsing

> Yeah, I guess other alternatives to `Wish this is outlined rgb([* $i 10],0,0)` are:
>
> - support spaces & tell people to use quotation marks if using them (or braces if not interpolating)`Wish this is outlined > "rgb([* $i 10], 0, 0)"`
> - move away from css syntax and use tcl `Wish this is outlined [rgb [* $i 10] 0 0]`
>
> Neither seems like an unqualified win to me :-/

_Originally posted by @osnr in https://github.com/FolkComputer/folk/issues/134#issuecomment-2098970326_