Fix code block rendering in dtr/release-notes

docker-trusted-registry/release-notes/prior-release-notes.md

@@ -106,9 +106,9 @@ Settings > Auth to perform the sync.
 
 * Fixed an issue where Trusted Registry administrators could not list all repositories in the registries. To list them, you must use the `catalog` API using a `bash` shell. The following example lists repositories in a Trusted Registry located at my.dtr.host where the user `admin` has password `password`.
 
-  ```
+```none
   bash -c 'host=vagrant.host admin=admin password=password token=$(curl -u $admin:$password -k "https://$host/auth/token?service=$host&scope=registry:catalog:*" | python2 -c "import json,sys;obj=json.load(sys.stdin);print obj[\"token\"]") && curl -k -H "Authorization: Bearer $token" "https://$host/v2/_catalog"'
-  ```
+```
 
 
 ## Version 1.4.3