Propagates links target from HTML message to plaintext version

[her-ur]

This functionality doesn't work correct. This HTML body:

<a href="https://www.nette.org">Nette.org</a><br>
<a href="https://www.google.com/">Google.com</a>

generates this plaintext version:

Google.com <https://www.nette.org">Nette.org

The test is passing because there are used single quotes in second link, if you change it to double quotes the result will be wrong.