Non-exhaustive enums: remove special repr. for enums w/ raw types
Non-exhaustive enums: remove special repr. for enums w/ raw types

This would make adding or removing a raw type an ABI-breaking change,
and since it's possible to do this without breaking source that
deserves its own discussion.

airspeedswift/swift-evolution,natecook1000/swift-evolution,Nirma/swift-evolution,apple/swift-evolution,aciidb0mb3r/swift-evolution,jtbandes/swift-evolution,jtbandes/swift-evolution,rballard/swift-evolution,natecook1000/swift-evolution,abertelrud/swift-evolution,apple/swift-evolution,DevAndArtist/swift-evolution,airspeedswift/swift-evolution,abertelrud/swift-evolution,Nirma/swift-evolution,anandabits/swift-evolution,rballard/swift-evolution,allevato/swift-evolution,ddunbar/swift-evolution,jckarter/swift-evolution,DevAndArtist/swift-evolution,hartbit/swift-evolution,hartbit/swift-evolution,bolshedvorsky/swift-evolution,jckarter/swift-evolution,ddunbar/swift-evolution,bolshedvorsky/swift-evolution,allevato/swift-evolution,aciidb0mb3r/swift-evolution,anandabits/swift-evolution