Author: Luca Bösch
MDL-64360 mod_assign: Add help icon to notify students checkbox.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=df0a2e21ddb683eb31c4dacdd4cb5d2931061265
http://github.com/moodle/moodle/commit/df0a2e21ddb683eb31c4dacdd4cb5d2931061265
+ 3.7 en [sendstudentnotifications_help,mod_assign]