Exposes the merkle proof logic from Open Zeppelin 5.x to rainlang as a single
subparsed word merkle-proof-verify.
The usage is as per the Open Zeppelin documentation, where the first argument to
merkle-proof-verify is the root, the second is the leaf and the tail is the
proof.
As merkle proofs have a length that depends on the size of the merkle tree the proof is for, the rainlang word is variadic. The whole tail is used as the proof but must be at least length 1.
Note that the merkle-proof-verify word returns 0 or 1 where 1 indicates
that the proof is valid. The rainlang author is responsible for applying ensure
to the return value to revert the transaction on invalid proofs if that is the
desired behaviour.