Mark HyperClockCache as production-ready (#10963)

Mark HyperClockCache as production-ready (#10963)

Summary:
After a couple minor bug fixes and successful productions roll-outs in a few places, I think we can mark this as production-ready. It has a clear value proposition for many workloads, even if we don't have clear advice for every workload yet.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10963

Test Plan: existing tests, comment changes only

Reviewed By: siying

Differential Revision: D41384083

Pulled By: pdillinger

fbshipit-source-id: 56359f01a57bb28de8697666b342382fac72ce6d