imply iridescent_hair -> iridescent

BUR #49881 is pending approval.

create implication iridescent_hair -> iridescent

Add implication for iridescent when tagging iridescent_hair.

If iridescent_hair is too similar to rainbow hair or multicolored hair, then let's nuke it instead

Iridescent would include iridescent hair, iridescent clothes, and everything else. We've moved away from umbrella tags like that because they're too broad and include too many disparate things (see: shiny, striped, etc).