Added guidance for GitLab.com administrator-only features
What does this MR do?
This MR standardizes on GitLab.com instead of GitLab SaaS: https://docs.gitlab.com/ee/development/documentation/styleguide/word_list.html#gitlabcom
It also adds an option for features that are available on GitLab.com but only used by GitLab.com administrators.
And it adds anchor links to call out that you need to do two things when adding feature flag content.
Edited by Suzanne Selhorn