api-ref: complete verification for diagnostics.inc

This completes the verification for the diagnostics API. As the
response is still dumping out raw hypervisor stats (for compatibility
https://github.com/openstack/nova/blob/7529b94f4a0be17fb3988362619f83b404ccad86/nova/api/openstack/compute/server_diagnostics.py#L38-L44)
the best we can say about the response is it's hypervisor specific and
don't use it.

In future we should use the standardized format that was defined
during the v3 effort.

Part of bp:api-ref-in-rst

Change-Id: Id2cca6a2f79542bec17a34aa3d31924e8ed7b9e5

api-ref/source/diagnostics.inc

@@ -1,7 +1,4 @@
 .. -*- rst -*-
-.. needs:parameter_verification
-.. needs:example_verification
-.. needs:body_verification
 
 ============================================
  Servers diagnostics (servers, diagnostics)
@@ -16,7 +13,9 @@ Show Server Diagnostics
 
 Shows basic usage data for a server.
 
-Policy defaults enable only users with the administrative role. Cloud providers can change these permissions through the ``policy.json`` file.
+Policy defaults enable only users with the administrative role. Cloud
+providers can change these permissions through the ``policy.json``
+file.
 
 Normal response codes: 200
 
@@ -33,8 +32,13 @@ Request
 Response
 --------
 
-**Example Server diagnostics: JSON response**
+The response format for diagnostics is backend hypervisor specific,
+and not well defined. This should be considered a debug interface
+only, and not relied upon by programmatic tools.
+
+**Example Server diagnostics**
+
+Below is an example of diagnostics for a libvirt based server instance.
 
 .. literalinclude:: ../../doc/api_samples/os-server-diagnostics/server-diagnostics-get-resp.json
    :language: javascript
-