Merge branch 'nfriend-add-info-about-release_mr_issue_urls' into 'master'

Add feature flag info for `release_mr_issue_urls`

See merge request gitlab-org/gitlab!43567

config/feature_flags/development/release_mr_issue_urls.yml

 ---
 name: release_mr_issue_urls
-introduced_by_url: 
-rollout_issue_url: 
-group: 
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/18727
+rollout_issue_url:
+group: group::release management
 type: development
 default_enabled: false