Fix some grammar in the help string.
Fix some grammar in the help string.

haxwithaxe/supybot,ProgVal/Limnoria-test,mazaclub/mazabot-core,frumiousbandersnatch/supybot-code,kblin/supybot-gsoc,Ban3/Limnoria,buildbot/supybot,mazaclub/mazabot-core,Ban3/Limnoria,ProgVal/Limnoria-test,prashantpawar/supybot-rothbot,raboof/supybot,jeffmahoney/supybot