doc: update outdated reference to NIST SP 800-131A
NIST SP 800-131A Rev. 1 has been withdrawn. Replace the reference with a link to NIST SP 800-131A Rev. 2.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
NIST SP 800-131A Rev. 1 has been withdrawn. Replace the reference with a link to NIST SP 800-131A Rev. 2.