message: docs: more datails on multihash code [skip ci]
diff: @@ -47,11 +47,13 @@ Examples of public keys in Iroha:
  +----------------+--------+----------+-------------------------+----------------------+
  | type | code | length | data | what Iroha recognises|
  +================+========+==========+=========================+======================+
  -| multihash key | ED | 20 | 62646464c35383430b... | ed25519/sha2 |
  +| multihash key | ED01 | 20 | 62646464c35383430b... | ed25519/sha2 |
  +----------------+--------+----------+-------------------------+----------------------+
  | raw 32 byte key| -- | -- | 716fe505f69f18511a... | ed25519/sha3 |
  +----------------+--------+----------+-------------------------+----------------------+
  +Note that code `0xED` is encoded as `ED01` by the rules of multihash format.
  +
  Private Keys
  ------------
  