Author: Shamim Rezaie
MDL-66360 core_grade: New message handler for grade notifications
http://git.moodle.org/gw?p=moodle.git;a=commit;h=966637264467ad10c31f0a72e548514d8f11bc9e
http://github.com/moodle/moodle/commit/966637264467ad10c31f0a72e548514d8f11bc9e
+ 3.8 en [messageprovider:gradenotifications,core]