Improve and unify the RESP error message

[git-hulk]

Search before asking

• [X] I had searched in the issues and found no similar issues.

Motivation

As mentioned in the comment: https://github.com/apache/kvrocks/blob/unstable/tests/gocase/util/server.go#L142, we should take care of different RESP error kinds to avoid introducing the protocol compatibility issues.

Solution

Use an unify function to return the RESP error message, like the following:

const std::string redis::Error(ErrorKind kind, const std::string &message) {
  switch(kind) {
    case ErrorKind::Loading: 
    case ErrorKind::NoProto:
    ...
    default:
  }
}

Are you willing to submit a PR?

• [X] I'm willing to submit a PR!

[PragmaTwice]

The problem is that we add ERR prefix for all msg returned by Status.

One solution is to add a new status code for no ERR prefix. (Or, add many status code for LOADING, NOPROTO...)

[git-hulk]

The problem is that we add ERR prefix for all msg returned by Status.

Yes

One solution is to add a new status code for no ERR prefix. (Or, add many status code for LOADING, NOPROTO...)

This also sounds good

[git-hulk]

closes by #2362