Git commits in Moodle 3.7.6 by Ferran Recio

commit 3c5d8d6602a03f950280814d9583fe0bc56ade63
Author: Ferran Recio <ferran@moodle.com>
Date:   Mon, 04 May 2020 22:54:54 +0800
Tag:    v3.7.6

MDL-68430 filter_mathjaxloader: update default CDN to 2.7.8