Low-level RPC changes
---------------------

- Error codes have been updated to be more accurate for the following error cases (#18466):
  - `signmessage` now returns RPC_INVALID_ADDRESS_OR_KEY (-5) if the
    passed address is invalid. Previously returned RPC_TYPE_ERROR (-3).
  - `verifymessage` now returns RPC_INVALID_ADDRESS_OR_KEY (-5) if the
    passed address is invalid. Previously returned RPC_TYPE_ERROR (-3).
  - `verifymessage` now returns RPC_TYPE_ERROR (-3) if the passed signature
    is malformed. Previously returned RPC_INVALID_ADDRESS_OR_KEY (-5).