Add validation rule for SedColor

[jonrkarr]

Color should be a 6 or 8 digit case-insensitive hexidecimal string (/[a-f0-9]{6,6}|[a-f0-9]{8,8}/i).

[luciansmith]

This is in the spec already; is there somewhere else you'd like to put this?

(see validation rule 25205, 25306, 25307, and 25404.)

We could mention that it's case-insensitive; that's not there yet.

[jonrkarr]

Sounds like I missed these rules