Author: John Okely
MDL-59725 assignsubmission_file: Improve accepted types string
http://git.moodle.org/gw?p=moodle.git;a=commit;h=29b31865d79f2ea172547791f06cb07b73a2493a
http://github.com/moodle/moodle/commit/29b31865d79f2ea172547791f06cb07b73a2493a
+ 3.4 en [filesofthesetypes,core_form]