This is just for reference while I figure out how to use the red link bot. Thanks to DEmersonJMFM for the help.
After adding the code to a personal js (I wouldn't bet it can be placed in a wiki's js), simply go to a page and under "My Tools" on the bottom bar, click "Fix Redlinks." In some cases (that I can't remember) the text doesn't fix 100% correct, but there's no problem generally (it doesn't work for templates or files). It's still page by page so it's your choice. If you use it, don't forget proper attribution of authors.