Docs: access go2rtc stream externally while using add-on blakeblacksh…

…ear#6208 (blakeblackshear#6209)

It took me quite a while to figure out why I couldn't access the go2rtc streams, maybe this saves others some time too.

Original question: blakeblackshear#6148

docs/docs/guides/configuring_go2rtc.md

@@ -71,6 +71,12 @@ go2rtc:
  - "ffmpeg:rtsp:https://user:[email protected]:554/cam/realmonitor?channel=1&subtype=2#video=copy#audio=copy#audio=aac"
 ```
 
+:::caution
+
+To access the go2rtc stream externally when utilizing the Frigate Add-On, for instance, through a WebRTC card or VLC, you must first enable the RTSP Restream port. You can do this by visiting the Frigate Add-On configuration page within Home Assistant and revealing the hidden options under the "Show disabled ports" section.
+
+:::
+
 ## Next steps
 
 1. If the stream you added to go2rtc is also used by Frigate for the `record` or `detect` role, you can migrate your config to pull from the RTSP restream to reduce the number of connections to your camera as shown [here](/configuration/restream#reduce-connections-to-camera).