Fixed documentation and options to address new sanity tests

- https://docs.ansible.com/ansible/latest/dev_guide/testing_validate-modules.html

Signed-off-by: Hideki Saito <saito@fgrep.org>

plugins/callback/timer.py

@@ -6,8 +6,8 @@ from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
 DOCUMENTATION = '''
-    callback: timer
-    callback_type: aggregate
+    name: timer
+    type: aggregate
     requirements:
       - whitelist in configuration
     short_description: Adds time to play stats