Adds the ability to declare 'authenticated' in controller doc block

[rahulhaque]

This commit adds the ability to include @authenticated in the controller doc block that will override any method under the controller just like @group. Updated the /docs/documenting.md to reflect the changes. Fixed the URL of body_params_1.png, body_params_2.png that were missing in Specifying request parameters section of document. Fixed a minor typo.