Docker: fix HTML escaping.

Author: lcrilly

pkg/docker/welcome.html

@@ -35,7 +35,7 @@ <h3>Check Current Configuration</h3>
            on the <a href="https://en.wikipedia.org/wiki/Unix_domain_socket">Unix socket</a> at
            <b>/var/run/control.unit.sock</b> inside the container.<br>
            To see the current configuration run:</p>
-        <pre>docker exec -ti <containerID> curl --unix-socket /var/run/control.unit.sock http://localhost/config</pre>
+        <pre>docker exec -ti &lt;containerID&gt; curl --unix-socket /var/run/control.unit.sock http://localhost/config</pre>
         </div>
 
         <hr>