Limit alert 22 to mainspace only

git-svn-id: svn://svn.code.sf.net/p/autowikibrowser/code/AWB@9951 5227b50d-9349-4574-b055-4b0a7525e11c
For https://en.wikipedia.org/wiki/Wikipedia_talk:AutoWikiBrowser/Bugs#KeyNotFoundException_in_Parsers.FixCategories

git-svn-id: svn://svn.code.sf.net/p/autowikibrowser/code/AWB@9952 5227b50d-9349-4574-b055-4b0a7525e11c