pjax problems : use `MutationObserver` instead

[payne911]

I just spent a few hours debugging my own Chrome Extension because the pjax events were not always being triggered.

Since I also had Lovely Forks enabled during my testing, I noticed you had the same problem as me, so I'm simply reaching out to you folks by pointing out to the commit's LOCs which resolved my issue: https://github.com/useful-forks/useful-forks.github.io/blob/65f19e50509a6a78bc7c71246247770312822c2f/plugin/useful-forks.js#L48-L68

Hopefully you'll find time to dig into this and integrate the MutationObserver in your extension as well 👍

If you want an easy test to reproduce what I'm talking about: go to your repository's main page, and click on any listed commit's title (see image).

You'll notice your extension's text will be gone.