Merge branch '416308-update-developer-documentation' into 'master'

Update developer documentation for User Caching during GitHub Import

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/130173



Merged-by: Evan Read <eread@gitlab.com>
Approved-by: Evan Read <eread@gitlab.com>
Co-authored-by: maddievn <mvanniekerk@gitlab.com>