Item description corrections

I went through itypedef.cpp and corrected every typo that I saw, plus one or two grammar fixes. I also removed all the double spaces after punctuation marks, because it’s bad form. :smiley:

Attached are the diffs. I had to split the changes into two files, as the original file exceeded the forum memory limit on attachments.

spellcheck1 (73.5 KB)

spellcheck2 (78 KB)

Thanks a ton! I’ve patched it into my repo and pushed to github, should show up in the next release.