Replace coupon amount display with a string

replace_coupon_amount_with_string.php

<?php // don't copy this line

add_filter( 'woocommerce_cart_totals_coupon_html', 'custom_cart_totals_coupon_html', 30, 3 );
function custom_cart_totals_coupon_html( $coupon_html, $coupon, $discount_amount_html ) {
    $discount_amount_html = '<span>Redeemed</span>'; 
    $coupon_html          = $discount_amount_html . ' <a href="' . esc_url( add_query_arg( 'remove_coupon', urlencode( $coupon->get_code() ), defined( 'WOOCOMMERCE_CHECKOUT' ) ? wc_get_checkout_url() : wc_get_cart_url() ) ) . '" class="woocommerce-remove-coupon" data-coupon="' . esc_attr( $coupon->get_code() ) . '">' . __( '[Remove]', 'woocommerce' ) . '</a>';
    return $coupon_html;
}