Author: Tim Hunt
MDL-59929 signup: inprove usability when duplicate email entered
http://git.moodle.org/gw?p=moodle.git;a=commit;h=abb4e64e3717322facf160b3a3b779b311fced4c
http://github.com/moodle/moodle/commit/abb4e64e3717322facf160b3a3b779b311fced4c
+ 3.3 en [emailexistssignuphint,core]
+ 3.3 en [emailexistshintlink,core]