In version 0.4.2 that was released yesterday, we’re already hooking to woocommerce_review_order_after_order_total, which displays the “you save” text at checkout below item summary and total.
If you still want to hook it to woocommerce_review_order_after_cart_contents, you can try the following code:
function thp_remove_default_you_save_checkout() {
remove_action( 'woocommerce_review_order_after_order_total', 'thp_ysxfw_cart_total_save', 99 );
}
add_action( 'init', 'thp_remove_default_you_save_checkout', 100 );
add_action( 'woocommerce_review_order_after_cart_contents', 'thp_ysxfw_cart_total_save', 100 );
Sorry for the late reply by the way, I was occupied with a lot of things in the past few months.