Author: Marina Glancy
MDL-32773 Add a help icon for button 'Set main file' in filemanager
http://git.moodle.org/gw?p=moodle.git;a=commit;h=0fb7a8a3dd01615dca18b67b5130d5c9a7761b33
http://github.com/moodle/moodle/commit/0fb7a8a3dd01615dca18b67b5130d5c9a7761b33
+ 2.6 en [setmainfile_help,core_repository]