TMaps with Enums as Keys should allow new entries by incrementing key instead of checking for defaul

I’ve come across this myself, quite annoying. Yes arrays make more sense to a programmer but if you want to present a nicer interface to the designers in BP and a few indirections aren’t a big deal then it would be nice to have sane handling of enums as keys.

And better handling of enums as array indices in BP, everybody wins!