De-PDF-ify AAAI papers

Reminder for later:

https://ojs.aaai.org/index.php/AAAI/article/view/20008/19767

should transform to

https://ojs.aaai.org/index.php/AAAI/article/view/20008/.

There probably needs to be a sanity check to avoid stripping the first number after "view".