message: docs: Improve ext_authz_filter docs
  This PR adds information on how to override the request timeout (which is sometimes more important than the connect_timeout, already mentioned.)
diff: @@ -34,6 +34,9 @@ A sample filter configuration for a gRPC authorization server:
  envoy_grpc:
  cluster_name: ext-authz
  + # Default is 200ms; override if your server needs e.g. warmup time.
  + timeout: 0.5s
  +
  .. code-block:: yaml
  clusters:
  @@ -42,6 +45,9 @@ A sample filter configuration for a gRPC authorization server:
  http2_protocol_options: {}
  hosts:
  - socket_address: { address: 127.0.0.1, port_value: 10003 }
  +
  + # This timeout controls the initial TCP handshake timeout - not the timeout for the
  + # entire request.
  connect_timeout: 0.25s
  A sample filter configuration for a raw HTTP authorization server:
  