message: docs: fix links in websocket documentation.
diff: @@ -12,11 +12,11 @@ upgrades as well. The new style of upgrades pass both the HTTP headers and the u
  through an HTTP filter chain. One may configure the
  :ref:`upgrade_configs <envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.upgrade_configs>`
  in one of two ways. If only the
  -`upgrade_type <envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.UpgradeConfigs.upgrade_type>`
  +:ref:`upgrade_type <envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.UpgradeConfig.upgrade_type>`
  is specified, both the upgrade headers, any request and response body, and WebSocket payload will
  pass through the default HTTP filter chain. To avoid the use of HTTP-only filters for upgrade payload,
  one can set up custom
  -`filters <envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.UpgradeConfigs.upgrade_type>`
  +:ref:`filters <envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.UpgradeConfig.filters>`
  for the given upgrade type, up to and including only using the router filter to send the WebSocket
  data upstream.
  