Author: Helen Foster
MDL-20514 help string rewording
http://git.moodle.org/gw?p=moodle.git;a=commit;h=1ab0d50b80c2391d3942067fc7c16911385cb5c4
http://github.com/moodle/moodle/commit/1ab0d50b80c2391d3942067fc7c16911385cb5c4
+ 2.0 en [aggregatetype_help,core_rating]
+ 2.0 en [rolewarning_help,core_rating]