docs: clarify Fabric docs TYPE usage (#3387)

Author: itzg

docs/types-and-platforms/server-types/fabric.md

@@ -1,21 +1,45 @@
-Enable [Fabric server](https://fabricmc.net/) mode by adding a `-e TYPE=FABRIC` to your command-line.
+A [Fabric server](https://fabricmc.net/) can be automatically downloaded, upgraded, and run by setting the environment variable TYPE to "FABRIC"
 
-```
-docker run -d -v /path/on/host:/data \
-    -e TYPE=FABRIC \
-    -p 25565:25565 -e EULA=TRUE --name mc itzg/minecraft-server
-```
+!!! example
+
+    Using `docker run` command line
+
+    ```
+    docker run -d -e EULA=TRUE -e TYPE=FABRIC -p 25565:25565 itzg/minecraft-server
+    ```
+    
+    In a compose file service:
+    
+    ```yaml
+    environment:
+      EULA: TRUE
+      TYPE: FABRIC
+    ```
 
 By default, the container will install the latest [fabric server launcher](https://fabricmc.net/use/server/), using the latest [fabric-loader](https://fabricmc.net/wiki/documentation:fabric_loader) against the minecraft version you have defined with `VERSION` (defaulting to the latest vanilla release of the game).
 
 A specific loader or launcher version other than the latest can be requested using `FABRIC_LOADER_VERSION` and `FABRIC_LAUNCHER_VERSION` respectively, such as:
 
-```
-docker run -d -v /path/on/host:/data ... \
-    -e TYPE=FABRIC \
-    -e FABRIC_LAUNCHER_VERSION=0.10.2 \
-    -e FABRIC_LOADER_VERSION=0.13.1
-```
+!!! example "Using launcher and loader versions"
+
+    With docker run
+
+    ```
+    docker run -d ... \
+        -e TYPE=FABRIC \
+        -e FABRIC_LAUNCHER_VERSION=0.10.2 \
+        -e FABRIC_LOADER_VERSION=0.13.1
+    ```
+    
+    In a compose file service:
+    
+    ```yaml
+    environment:
+      EULA: TRUE
+      TYPE: FABRIC
+      FABRIC_LAUNCHER_VERSION: 0.10.2
+      FABRIC_LOADER_VERSION: 0.13.1
+    ```
 
 !!! note