fix header

Author: cachai2

articles/container-apps/ingress-how-to.md

@@ -163,7 +163,6 @@ Disable ingress for your container app by omitting the `ingress` configuration p
 ::: zone-end
 
 ## <a name="use-additional-tcp-ports"></a>Use additional TCP ports (preview)
-## Use additional TCP ports (preview)
 
 You can expose additional TCP ports from your application. To learn more, see the [ingress concept article](ingress-overview.md#additional-tcp-ports).