Remove /notify from client-server API

api/push-gateway/push_notifier.yaml

@@ -189,5 +189,3 @@ paths:
                 items:
                   type: string
                   description: A pushkey
-      tags:
-        - Push notifications

specification/modules/push.rst

@@ -404,12 +404,6 @@ sender and content rules)::
 Server behaviour
 ----------------
 
-This describes the format used by "HTTP" pushers to send notifications of
-events to Push Gateways. If the endpoint returns an HTTP error code, the
-homeserver SHOULD retry for a reasonable amount of time using exponential-backoff.
-
-{{push_notifier_http_api}}
-
 Push Gateway behaviour
 ----------------------