8aa893ebd0 Remove repetition from sha256t_hash_newtype macro (Tobin C. Harding)
Pull request description:
The `sha256t_hash_newtype` macro is hard to reason about because we allow repetition so which tag goes with which type is slightly obscure.
Remove repetition and call the macro three times.
Internal change in `bitcoin`, API change in `hashes`.
Fix#2811
ACKs for top commit:
apoelstra:
ACK 8aa893ebd0 nice, small diff
Tree-SHA512: b38e7c307ac7288b4a5c1c3170ad6aa54c62bd3198922ec8bb091867b230bb9149f7dc996766fc8fa20a1af18b318c475b3e83e2689d322b7f4af0d5cb588e50