Merge pull request #9464 from SvenDowideit/sven_tries_webhooks

Add some extra details to webhook docs
(cherry picked from commit 84dc2c83cb208144763740f12354d3e37d9fa135)

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
Merge pull request #9518 from fredlf/post-1.3.2-docs-update-02-part2

Merge pull request #9464 from SvenDowideit/sven_tries_webhooks