Steps to reproduce:

1. Edit a page with VisualEditor.
2. Click Insert → Basic Reference.
3. Paste a text containing a URL, e.g. "From Phabricator project: https://phabricator.wikimedia.org/project/view/483/.".

Actual result:
The URL is not a link.

Expected result:
The URL is converted into a link.

Additional information:
This was noted when copying from Google Docs. Even if the URL was a link in Docs, this doesn't carry over when pasting it in the reference popup.