message: docs: correct the API link for http ExtAuthz filter documentation
  The original one was pointed to network instead of http one
diff: External Authorization
  ======================
  * External authorization :ref:`architecture overview <arch_overview_ext_authz>`
  -* :ref:`HTTP filter v3 API reference <envoy_v3_api_msg_extensions.filters.network.ext_authz.v3.ExtAuthz>`
  +* :ref:`HTTP filter v3 API reference <envoy_v3_api_msg_extensions.filters.http.ext_authz.v3.ExtAuthz>`
  * This filter should be configured with the name *envoy.filters.http.ext_authz*.
  The external authorization filter calls an external gRPC or HTTP service to check whether an incoming
  