Git commits in Moodle 3.5.3 by Peter Spicer

commit 7331c8af569e1430bad50fc808165bf2cfbc999a
Author: Peter Spicer <peter.spicer@catalyst-eu.net>
Date:   Wed, 10 Oct 2018 17:32:43 +0800
Tag:    v3.5.3

MDL-63451 core_message: Properly escape URLs for notification popup