engine-cli: fix docker volume prune output without --all

Author: rmbruntz

data/engine-cli/docker_volume_prune.yaml

@@ -60,7 +60,7 @@ examples: |-
     Are you sure you want to continue? [y/N] y
     Deleted Volumes:
     07c7bdf3e34ab76d921894c2b834f073721fccfbbcba792aa7648e3a7a664c2e
-    my-named-vol
+    2b9af34974f8a2340a35400a1aa2345252837914391192f88d852b85385ffcaa
 
     Total reclaimed space: 36 B
     ```