Remove '/category/' from category archive url Wordpress

functions.php

<?php
/*
 * Remove '/category/' from category archive url
 * */
function remcat_function($link) {
    return str_replace("/category/", "/", $link);
}
add_filter('user_trailingslashit', 'remcat_function');

function remcat_flush_rules() {
    global $wp_rewrite;
    $wp_rewrite->flush_rules();
}
add_action('init', 'remcat_flush_rules');

function remcat_rewrite($wp_rewrite) {
    $new_rules = array('(.+)/page/(.+)/?' => 'index.php?category_name='.$wp_rewrite->preg_index(1).'&paged='.$wp_rewrite->preg_index(2));
    $wp_rewrite->rules = $new_rules + $wp_rewrite->rules;
}
add_filter('generate_rewrite_rules', 'remcat_rewrite');