Fixes for plaintext email generation

* The <br /> tag will now generate a newline
* When you have <span>Test </span> the space inside the tag will not be deleted
* Attention: DO NOT wrap tags in <p>. Keep everything at the root level and
  make it a sequence of <span></span><a></a><br />.

  Unfortunately this is necessary because the parser cannot handle nested tags
  nicely. If you have <p>Text1 <a ...></a></p> the parser would see that the
  closing tag for "Text1" is <p> and therefore append a newline, although
  there is actually more content coming before the closing tag.
Released v2.42.3