Author: John Okely
MDL-49983 admin: Improve user menu grades setting language strings
http://git.moodle.org/gw?p=moodle.git;a=commit;h=6289c2ea9403400289b6a6ff1aa6d28f29138725
http://github.com/moodle/moodle/commit/6289c2ea9403400289b6a6ff1aa6d28f29138725
+ 2.9 en [mygrades,core_grades]
+ 2.9 en [mygrades_desc,core_grades]