message: docs: note internal_address_config setting in header sanitization docs
  Risk Level: low
  Testing: n/a
  Docs Changes: updated
  Release Note: n/a
  Fixes:
diff: @@ -9,7 +9,11 @@ result in addition, removal, or modification. Ultimately, whether the request is
  or external is governed by the :ref:`x-forwarded-for <config_http_conn_man_headers_x-forwarded-for>`
  header (please read the linked section carefully as how Envoy populates the header is complex and depends on the
  :ref:`use_remote_address
  -<envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.use_remote_address>` setting).
  +<envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.use_remote_address>`
  +setting). In addition, the
  +:ref:`internal_address_config
  +<envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.internal_address_config>`
  +setting can be used to configure the internal/external determination.
  Envoy will potentially sanitize the following headers:
  