Document features of the code-owners plugin on the about page
Document features of the code-owners plugin on the about page

Signed-off-by: Edwin Kempin <d43fb6c98c97e553b671ed9a9318100f1de386e7@google.com>
Change-Id: Iafae132554101586447e6c79cae597b3d93e48a4

GerritCodeReview/plugins_code-owners,GerritCodeReview/plugins_code-owners,GerritCodeReview/plugins_code-owners,GerritCodeReview/plugins_code-owners