docs(reference): Fix GET /v1/keys/ response

Author: Joshua Anderson

docs/reference/api-v1.5.rst

@@ -1152,9 +1152,12 @@ Example Response:
 
 .. code-block:: console
 
-    {
+    HTTP/1.1 201 CREATED
     DEIS_API_VERSION: 1.5
     DEIS_PLATFORM_VERSION: 1.8.0-dev
+    Content-Type: application/json
+
+    {
         "count": 1,
         "next": null,
         "previous": null,