Show Back to Page Link in WordPress Blank Comment Posting

functions.php

<?php
add_action( 'pre_comment_on_post', function ( $comment_post_ID ) {
    $go_back = sprintf( __( '<br><a href="javascript:history.go(-1)">Back to "%s" Article</a>' ), get_the_title( $comment_post_ID ) );
    // Part-copied from "wp-comments-post.php", with $go_back tagged onto error strings.
    $comment_author       = ( isset($_POST['author']) )  ? trim(strip_tags($_POST['author'])) : null;
    $comment_author_email = ( isset($_POST['email']) )   ? trim($_POST['email']) : null;
    $comment_content      = ( isset($_POST['comment']) ) ? trim($_POST['comment']) : null;
    $user = wp_get_current_user();
    if ( get_option('require_name_email') && !$user->exists() ) {
        if ( 6 > strlen( $comment_author_email ) || '' == $comment_author ) {
            wp_die( __( '<strong>ERROR</strong>: please fill the required fields (name, email).' ) . $go_back, 200 );
        } elseif ( ! is_email( $comment_author_email ) ) {
            wp_die( __( '<strong>ERROR</strong>: please enter a valid email address.' ) . $go_back, 200 );
        }
    }
    if ( '' == $comment_content ) {
        wp_die( __( '<strong>ERROR</strong>: please type a comment.' ) . $go_back, 200 );
    }
} );