Add aliases for nonatomic versions of mget/mset

[daveisfera]

Pull Request check-list

• Does $ tox pass with this change (including linting)? Not sure how to run this but I believe it's ok
• Do the CI tests pass with this change (enable it first in your forked repo and wait for the github action build to finish)? Not sure how to run these
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)? Don't believe there's a needed change here
• Is there an example added to the examples folder (if applicable)? Existing example should suffice
• Was the change added to CHANGES file?

Description of change

RedisCluster provides functions for handling when multiple keys are used with separate key slots, so alias the single server versions so code can use them without caring which type of server is running