75b49efb3d Implement `Hash` for all array newtypes (elsirion)
Pull request description:
I pondered putting the impl into the array type macro together with `(Partial)Eq`, but that would have meant removing other implementations and potentially implementing it for types where it is not wanted. The drawback of the separate impl is that it is more disconnected from the `(Partial)Eq` impl and could theoretically diverge (although unlikely in case of such a simple type) which would break the trait's contract.
ACKs for top commit:
apoelstra:
ACK 75b49efb3d
Tree-SHA512: 44d1bebdd3437dfd86de8b475f12097c4a2f872905c822a9cde624089fdc20f68f59a7734fdcc6f3a17ed233f70f63258dfd204ca269d2baf8002ffc325ddc87