Documentation: use generic url in channels dvr widget docs (#3434)

docs/widgets/services/channelsdvrserver.md

@@ -8,5 +8,5 @@ Learn more about [Channels DVR Server](https://getchannels.com/dvr-server/).
 ```yaml
 widget:
   type: channelsdvrserver
-  url: http://192.168.1.55:8089
+  url: http://server.host.or.ip:port
 ```