This is needed to avoid the URL filter detecting wrong link boundaries
as the escape filter would change eg. "<http://kde.org/>" to
&lt;http://kde.org/&gt; and then the URL filter would detect
"http://kde.org/&gt" as the actual link.

Switching the order wouldn't help because the escape filter would escape
the newly inserted <a href...> links and the user would
get &lt;a href.../a&gt; and no clickable links.

Therefore we first detect the links, replace them with placeholders,
then escape everything, then replace placeholders with actual links.

Reviewed-by: David Edmundson
BUG: 329875
FIXED-IN: 0.8.0