[PasswordReveal] color property not listed but used by sites in edgehtml-based Edge

[BoCupp-Microsoft]

trafficstars

The color property is used by netflix to style the -ms-reveal pseudo-element, but this proposal doesn't list it. We should consider adding it.

[travisleithead]

@gregwhitworth would love your opinion on whether this should make the cut; is there an alternative that Netflix could use?