Author: Sara Arjona
MDL-83518 mod_assign: Add missing lang strings for SMS
http://git.moodle.org/gw?p=moodle.git;a=commit;h=fe3ce8d23e8923ff98db95736f047d67a68d30c4
http://github.com/moodle/moodle/commit/fe3ce8d23e8923ff98db95736f047d67a68d30c4
+ 5.0 en [feedbackavailableanonsms,mod_assign]
+ 5.0 en [submissioncopiedsms,mod_assign]