Redirect WordPress posts to the editor if someone types /edit at the end of the permalink

functions.php

<?php
function init_url_rewrite_rule(){
    add_rewrite_endpoint( 'edit',EP_PERMALINK | EP_PAGES | EP_ATTACHMENT );
    if(get_option("EDIT_REWRITE_RULE")!=1){
        flush_rewrite_rules();
        update_option("EDIT_REWRITE_RULE",1);
    }
}

function redirect_edit_url(){
    global $wp_query;

    if(is_single() || is_page() || is_attachment()){
        if(isset($wp_query->query_vars['edit'])) {
            $url = get_edit_post_link(0,'&');
            wp_redirect($url);
        }
    }
}
add_action("init","init_url_rewrite_rule");
add_action("template_redirect","redirect_edit_url");