docs: Update README.md

Author: NGPixel

docker/README.md

@@ -164,11 +164,14 @@ If you already have a clone, such as from a previous codesprint, and are updatin
 * `rm ietf/settings_local.py`   # The startup script will put a new one, appropriate to the current release, in place
 * Execute the `Clean all` sequence above.
 
-If the dev environment fails to start, even after running the `Clean all` sequence above, you can fully purge all docker cache, containers, images and volumes by running:
+If the dev environment fails to start, even after running the `Clean all` sequence above, you can fully purge all docker cache, containers, images and volumes by running the command below.
+
+> [!CAUTION]
+> Note that this will delete everything docker-related, including non-datatracker docker resources you might have.
+
 ```sh
 docker system prune -a --volumes
 ```
-Note that this will delete everything docker-related, including non-datatracker docker resources you might have.
 
 ### Accessing PostgreSQL Port