auto add "referrer header" for url link

[g10996694]

Sometimes, the url link in the field URL has no referrer header (http://) etc.
So, when we click the link icon, JabRef showed the error that

Windows cannot find '....'. Make sure you typed the name correctly, and
then try again. To search for a file, dick the Start button, and then dick Search.

Perhaps this can be avoided by adding automatically the referrer header.
Tested on the 2.11.1
Thank you

[stefan-kolb]

Personally, I'm not sure if we should add a protocol by default if it is missing. It is just a bad URL then and should be fixed by the user to get a correct field value?! Also, how can we know which protocol should be used?

[koppor]

This is how Chrome works. Why not just trying to add http:// if the protocol is missing?

[stefan-kolb]

It's not displayed in Chrome, but prepended if you copy the URL.
Why not:

• Do not foster unsecure http:// protocol
• Can we be sure it is not another protocol, like a file path?

[g10996694]

@stefan-kolb you are right. perhaps the right way would be check if it is a file path or url link.
thank you

[koppor]

Add it to ntegrity check

Eventually, we add it to cleanup to add http before, which whould match 80% of the cases.