Git commits in Moodle 3.7.5 by Michael Milette

commit 39fd21e4ff09aa3a042d081c68e3c6933c489def
Author: Michael Milette <michael.milette@tngconsulting.ca>
Date:   Tue, 14 Jan 2020 05:19:31 +0800
Tag:    v3.7.5

MDL-66858 master: Enable <header> tags in Atto editor.