Fix message about incorrect usage of dihedral type 9

The warning printed the wrong type number: 4 instead of 9. Also it
didn't clarify that 9 only combines consecutive lines.

Change-Id: Ie65a050c978f162acf9f9a2329dde286c068438c
Merge release-4-6 into release-5-0

Change-Id: Ie72eccf57febab7b7ac8092ce55988b9cb2737af
Merge "Merge release-4-6 into release-5-0" into release-5-0