Automatic site-link detection not working

[NickLanger1990]

Description

I tried to use the new feature automatic site-link detection but cant get it to work.

Steps to reproduce

1. go into html mode and paste <a href="/testlink" target="_blank">TestLink</a> and save. it doesnt matter if the link is relative or absolute.
2. click on edit link.
3. the link is still the same as before. multisite is selected in site.
4. if i change multsite to my site a "@4" is appended to the url.
5. if i change this changes in the modal and reopen it "mailto:" is prepended to the url.
6. if go in html mode again in a field i already edited and change something again and click with my cursor anywhere in the field my recent changes get revoked.

Additional info

• Craft version: Craft Pro 3.7.28
• PHP version: 8.0.13
• Database driver & version: MySQL 5.7.36
• Plugins & versions: Redactor 2.9.1

[andris-sevcenko]

Relative links won't work, because Craft uses the absolute URL to figure out which site a potential element match should be looked up by the URI.

I also improved the behavior of the site dropdown - it will now appear only for links that look like they are element references for elements that are localized.