Redis redis-cli --help should not output to stderr and return failing exit status

Using redis 5.0.0

redis-cli --help currently outputs all information on stderr and return 1 as exit status.

"All" other CLI tools display the help information on the stdout. Which is useful if you want to manipulate directly the data (grepping for example, without needing to do redirections) The exit status code is usually 0 too, which makes sense.