Documentation: Add details to Gluetun widget docs (#2357)

---------

Co-authored-by: shamoon <4887959+shamoon@users.noreply.github.com>

docs/widgets/services/gluetun.md

@@ -3,12 +3,14 @@ title: Gluetun
 description: Gluetun Widget Configuration
 ---
 
-Requires [HTTP control server options](https://github.com/qdm12/gluetun-wiki/blob/main/setup/advanced/control-server.md) to be enabled.
+!!! note
+
+    Requires [HTTP control server options](https://github.com/qdm12/gluetun-wiki/blob/main/setup/advanced/control-server.md) to be enabled. By default this runs on port `8000`.
 
 Allowed fields: `["public_ip", "region", "country"]`.
 
 ```yaml
 widget:
   type: gluetun
-  url: http://gluetun.host.or.ip
+  url: http://gluetun.host.or.ip:port
 ```