Git commits in Moodle 3.9.15 by Andrew Nicols

commit f4df13fb6c3854fcfbc90c91bdafceb4dc492880
Author: Andrew Nicols <andrew@nicols.co.uk>
Date:   Fri, 03 Jun 2022 11:06:38 +0800
Tag:    v3.9.15

weekly release 3.9.14+