Add first-day-of-week admin area config note
What does this MR do?
Completes the docs for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22755, until the admin area is fully documented.
Related issues
Related to: https://gitlab.com/gitlab-org/gitlab-ce/issues/57874.
Author's checklist
Review checklist
-
Your team's review (required) -
PM's review (recommended, but not a blocker) -
Technical writer's review (required)
Edited by Evan Read