feat: add validator for surface:colour

[cuatim]

closes #2634

[Famlam]

You probably want to either add rainbow twice to the regex rule (if you want to allow rainbow;red whatever that means) or instead special-case it by adding [surface:colour!=rainbow] instead, at the end of the rule. My preference would be the latter.

Can you add way surface:colour=rainbow to the tests (assertNoMatch-rules) at the bottom?

[cuatim]

instead special-case it by adding [surface:colour!=rainbow] instead, at the end of the rule. My preference would be the latter.

agreed. done.

Can you add way surface:colour=rainbow to the tests (assertNoMatch-rules) at the bottom?

added as well!

[frodrigo]

Thank you all.
Merged, but not deployed, yet.