Author: Paul Holden
MDL-66025 user: require message content in bulk action.
Also import missing 'core/notification' dependency.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=b70b06bc61a53190e7dfa2f1ca3894588fafc183
http://github.com/moodle/moodle/commit/b70b06bc61a53190e7dfa2f1ca3894588fafc183
+ 3.9 en [messagetextrequired,core_message]