Author: Marina Glancy
MDL-32867 Display a list of references pointing to the file in filemanager
http://git.moodle.org/gw?p=moodle.git;a=commit;h=9dbdf31f8c1569af0bead5bf47a58d74acd2fb64
http://github.com/moodle/moodle/commit/9dbdf31f8c1569af0bead5bf47a58d74acd2fb64
+ 2.3 en [referencesexist,core_repository]
+ 2.3 en [referenceslist,core_repository]
+ 2.3 en [undisclosedreference,core_repository]