linkify emailed thread notifications

[chconnor]

Hi -- minor nit here: when a new comment is made on a thread, I get the email notification.

It's Content-Type text/html, and the raw content is something like:

Dear chconnor,<br />
<br />
claydoh has quoted you in the discussion located at:<br />
https://www.kubuntuforums.net/node/676924<br />
<br />​

...I'm sure many mail clients linkify the URL automatically, but Thunderbird does not. It would be nice if that was in a proper <a href=> tag to avoid having to select/copy/paste to open the link.