"Auto detect" option in telephone input does nothing

When configuring a telephone input with the checkbox "Enhance support for international phone numbers" there is an option to set the initial country to "Auto detect" but this actually does nothing.

To make it work a geoIpLookup function must be specified in Drupal.webform.intlTelInput.options as per the documentation https://github.com/jackocnr/intl-tel-input#options.

Since no such function is described, this should be documented when configuring the telephone element so that people know the option won't do anything unless they specifically add their own custom geoIP function to drupalSettings.