Make TypedKey an actual Key

[kennytv]

Take an example from the data component api:

Equippable.Builder equippable = itemStack.getData(DataComponentTypes.EQUIPPABLE).toBuilder()
    .equipSound(Sound.ENTITY_GHAST_HURT.key());

For the equipment sound and similar methods taking some kind of key, we have wonderful Key classes that unfortunately aren't actually keys. So Sound.TYPE.key() ends up being less annoying to use than SoundEventKeys.TYPE.key() (though still annoying). Being able to actually use SoundEventKeys.TYPE as an argument makes it more likely for people to prefer it over the enums/enum-like registry values

Key extends Keyed, so this won't break existing plugins