Document the syntax of the find-owners backend
Document the syntax of the find-owners backend

Signed-off-by: Edwin Kempin <d43fb6c98c97e553b671ed9a9318100f1de386e7@google.com>
Change-Id: Icc4616b6f0046e700adbcc8eb3b356d2b4d9135d

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