Autolink parser converts URLs with `@` in them to mailto

[maxking]

The current implementation of parse_auto_link in the parser appends mailto: to the URL without checking if it is an email or not. The simplest check for @ in the text doesn't always work.

Since @ is a valid character in regular URLs, I would consider this a bug. At the very least, we should check if the URL text has an HTTP(s) protocol before appending mailto to it.