Git commits in Moodle 3.9.4 by David Matamoros

commit e80e613f65552ea3580ef35fa8b2a9a71271389a
Author: David Matamoros <davidmc@moodle.com>
Date:   Sun, 22 Nov 2020 23:22:03 +0800
Tag:    v3.9.4

MDL-69411 core_message: Fix return structure for empty result set


commit 9e597d3658d67ab9acb41a99b89351fcc72a9bf8
Author: David Matamoros <davidmc@moodle.com>
Date:   Sat, 21 Nov 2020 00:09:37 +0800
Tag:    v3.9.4

MDL-63683 enrol: Fix plugin settings when no role has student archetype