Try to match if the part after @ is a valid ref (reject treating URL parts as refs).

[matteius]

Try fixing the other part of #5849

The issue

Sometimes VCS urls have an @ symbol for netloc auth component, try to differentiate if its a valid ref.

The checklist

• Associated issue
• A news fragment in the news/ directory to describe this fix with the extension .bugfix.rst, .feature.rst, .behavior.rst, .doc.rst. .vendor.rst. or .trivial.rst (this will appear in the release changelog). Use semantic line breaks and name the file after the issue number or the PR #.