function to add a cart message in the added to cart popup
/* this action add cart message in the added to cart popup */
add_action('yith_wacp_before_popup_content', 'yith_wacp_before_popup_content');
function yith_wacp_before_popup_content(){
if( class_exists('YWCM_Cart_Messages')){
global $YWCM_Instance;
$YWCM_Instance->print_message();
}
}