Rated 4 out of 5 stars
Would be much more useful if rules were customizable, but for the impatient, who can't wait for cfinke ;-): extract chrome/url-fixer.jar (simple zip will do), look at content/url-fixer.js.
From around line 134, you see the rules. Play with them.
Note: all your modifications will probably be overwritten at next update.
Note: do NOT ask for support about the rule syntax.
Note: use it on your own risk! If it is not working (at all) a remove+install extension might solve the issue.
I write these tips only for those, who wants to use this excellent feature, and are not afraid of some coding.
Grats and creds to cfinke!
I've developed a premium version of URL Fixer that allows you to customize the correction rules: http://www.chrisfinke.com/marketplace/url-fixer-plus.php