Fix GUID/PGID mismatch in 7 more app guides missed by the earlier pass

content/en/3.serveex/5.media/1.jellyfin.md

@@ -59,7 +59,7 @@ services:
     container_name: jellyfin
     environment:
       - PUID=${PUID}
-      - PGID=${GUID}
+      - PGID=${PGID}
       - TZ=Europe/Paris
     volumes:
       - /srv/docker/jellyfin/config:/config
@@ -86,7 +86,7 @@ services:
 
 ### Set your environment variables
 
-Find your PUID and GUID by running:
+Find your PUID and PGID by running:
 
 ```bash [Terminal]
 id username
@@ -96,7 +96,7 @@ Fill in your `.env` file with the retrieved values, for example:
 
 ```properties [.env]
 PUID=1000
-GUID=1000
+PGID=1000
 ```
 
 Deploy the stack. The local interface is available at `http://yourserverip:8096`.