Fix formatting

I set Astyle in codeblocks to the options listed in contributing.md, so
that makes things look the way you mentioned they should.  But when I
tried setting return to just 100, it quit working.  I tried a couple
variations, and the only way this works right is with "return
it->charges -=100;".  If this is a bug, I think it must be somewhere
else in Cata's code, because it doesn't seem to be here.