EDD show automatic purchase button below content on download category archives

gistfile1.php

<?php // DO NOT COPY THIS LINE

/**
 * remove original filter that adds purchase button below download content
 */
remove_filter( 'the_content', 'edd_after_download_content' );

/**
 * add new filter that adds "is_archive()" to the conditional so
 * that the button will also show on downloads archives
 */
function custom_edd_after_download_content( $content ) {
    global $post;

    if ( $post && $post->post_type == 'download' && ( is_singular( 'download' ) || is_archive( 'download' ) ) && is_main_query() && !post_password_required() ) {
        ob_start();
        do_action( 'edd_after_download_content', $post->ID );
        $content .= ob_get_clean();
    }

    return $content;
}
add_filter( 'the_content', 'custom_edd_after_download_content' );