Author: John Okely
MDL-39913 assign: Add help on filetype submissions
http://git.moodle.org/gw?p=moodle.git;a=commit;h=62e87ae4b8b3eeca65bd63cbfdccc5b9b2c5d982
http://github.com/moodle/moodle/commit/62e87ae4b8b3eeca65bd63cbfdccc5b9b2c5d982
+ 3.3 en [acceptedfiletypes_help,assignsubmission_file]