**Steps to replicate the issue** (include links if applicable):
* Case 1: Using Visual Editor's automatic reference insertion, paste a shortened YouTube URL, like `https://youtu.be/dQw4w9WgXcQ`
* Case 2: Also try with the full video URL, `https://www.youtube.com/watch?v=dQw4w9WgXcQ`
**What happens?**:
* Case 1: The reference is correctly formatted for you, and the link goes to the full video URL (`https://www.youtube.com/watch?v=dQw4w9WgXcQ`), but you are also shown a scary red warning saying that the site is "considered unreliable", and can't insert the reference.
* Case 2: The reference is formatted in exactly the same way, but no warning is shown and you can insert the reference.
**What should have happened instead?**:
* No warning should be shown for youtu.be URLs when the resulting URL doesn't include `youtu.be`
**Software version** (skip for WMF-hosted wikis like Wikipedia):
**Other information** (browser name/version, screenshots, etc.):