Merge branch 'docs-approval-rules-dev-guide' into 'master'

Remove tier and clarify dev doc

See merge request gitlab-org/gitlab!51968

doc/development/approval_rules.md

@@ -4,7 +4,7 @@ group: Source Code
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
-# Approval Rules **(STARTER)**
+# Approval Rules development guide
 
 This document explains the backend design and flow of all related functionality
 about [merge request approval rules](../user/project/merge_requests/merge_request_approvals.md).