Merge branch 'DarwinJS-clarify-opensearch-service-linked-role-docs' into 'master'

Advanced search and AWS OpenSearch config docs update

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/149183



Merged-by: Russell Dickenson <rdickenson@gitlab.com>
Approved-by: Changzheng Liu <cliu@gitlab.com>
Approved-by: Russell Dickenson <rdickenson@gitlab.com>
Reviewed-by: Russell Dickenson <rdickenson@gitlab.com>
Reviewed-by: Changzheng Liu <cliu@gitlab.com>
Reviewed-by: Terri Chu <tchu@gitlab.com>
Co-authored-by: Terri Chu <tchu@gitlab.com>
Co-authored-by: DarwinJS <dsanoy@gitlab.com>