Author: Andrew Davis
quiz MDL-23827 made a string grammatically correct
http://git.moodle.org/gw?p=moodle.git;a=commit;h=6c2f430931fa6fdbce54cc0b1e8dc4e4856c5d46
http://github.com/moodle/moodle/commit/6c2f430931fa6fdbce54cc0b1e8dc4e4856c5d46
+ 2.0 en [feedbackerrororder,mod_quiz]