redirect to another page on webform submit using [current-page:query:?] token
I've found that no token is required for this...

You can select Confirmation page as the redirect location, then the ?destination= parameter will just work. Not sure that this is a documented feature, though.

See also https://drupal.stackexchange.com/questions/120466/webform-redirect-to-referring-page-on-submit-not-showing-message which highlights a downside to this method.