GitHub PR File Randomizer par Toby Crawley

The extension will automatically run on GitHub PR files pages
(https://github.com//pull//files) and randomly shuffle the file order each
time you load or refresh the page.

Rationale

Files on pull requests are always sorted alphabetically, and reviewers typically
review from top to bottom. I posit that later files may not get as thorough of a
review as earlier ones, especially for large PRs. This aims to help with that.