Merge #18466: rpc: fix invalid parameter error codes for {sign,verify}message RPCs

a5cfb40e27bd281354bd0d14d91f83efb6bfce9f doc: release note for changed {sign,verify}message error codes (Sebastian Falbesoner)
9e399b9b2d386b28c0c0ff59fc75d31dbec31d9c test: check parameter validity in rpc_signmessage.py (Sebastian Falbesoner)
e62f0c71f10def124b1c1219d790cef246a32c3e rpc: fix {sign,message}verify RPC errors for invalid address/signature (Sebastian Falbesoner)

Pull request description:

  RPCs that accept address parameters usually return the intended error code `RPC_INVALID_ADDRESS_OR_KEY` (-5) if a passed address is invalid. The two exceptions to the rule are `signmessage` and `verifymessage`, which return `RPC_TYPE_ERROR` (-3) in this case instead. Oddly enough `verifymessage` returns `RPC_INVALID_ADDRESS_OR_KEY` when the _signature_ was malformed, where `RPC_TYPE_ERROR` would be more approriate.

  This PR fixes these inaccuracies and as well adds tests to `rpc_signmessage.py` that check the parameter validity and error codes for the related RPCs `signmessagewithprivkey`, `signmessage` and `verifymessage`.

  master branch:
  ```
  $ ./bitcoin-cli signmessage invalid_addr message
  error code: -3
  error message:
  Invalid address
  $ ./bitcoin-cli verifymessage invalid_addr dummy_sig message
  error code: -3
  error message:
  Invalid address
  $ ./bitcoin-cli verifymessage 12c6DSiU4Rq3P4ZxziKxzrL5LmMBrzjrJX invalid_sig message
  error code: -5
  error message:
  Malformed base64 encoding
  ```
  PR branch:
  ```
  $ ./bitcoin-cli signmessage invalid_addr message
  error code: -5
  error message:
  Invalid address
  $ ./bitcoin-cli verifymessage invalid_addr dummy_sig message
  error code: -5
  error message:
  Invalid address
  $ ./bitcoin-cli verifymessage 12c6DSiU4Rq3P4ZxziKxzrL5LmMBrzjrJX invalid_sig message
  error code: -3
  error message:
  Malformed base64 encoding
  ```

ACKs for top commit:
  laanwj:
    Code review ACK a5cfb40e27bd281354bd0d14d91f83efb6bfce9f
  meshcollider:
    utACK a5cfb40e27bd281354bd0d14d91f83efb6bfce9f

Tree-SHA512: bae0c4595a2603cea66090f6033785601837b45fd853052312b3a39d8520566c581994b68f693dd247c22586c638c3b7689c849085cce548cc36b9bf0e119d2d

0 files changed, 0 insertions, 0 deletions