Follow-up from "Documentation for Prometheus Service Discovery"

The following discussion from !29811 (merged) should be addressed:

• @axil started a discussion:

  What are Y.Y.Y.Y and Z.Z.Z.Z? Is this the info from https://docs.gitlab.com/ee/administration/high_availability/database.html#consul-information?

  We don't mention that anywhere in this doc (and the others).