isPRFiles - Handle new URL format

[SunsetTechuila]

follow-up to #212

[SunsetTechuila]

I should say that this repo has one of the most confusing error messages I've ever seen. What's wrong?

[fregante]

All test URLs are tested across all detections to ensure there are not false positives/negatives.

The error message cannot be any clearer, it literally asks a question and tells you how to fix it:

Is this URL `isCommit`?
	/refined-github/refined-github/pull/148/changes/e1aba6f

• Yes? Add it to the `addTests()` array.
• No? The `isCommit` detection is wrong and should be fixed.