function ucuruza_menus() {
    register_nav_menus(array(
        'main-menu' => 'Main Menu'
    ));
}

add_action('after_setup_theme', 'ucuruza_menus');<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="https://ucuruza.com/wp-sitemap-index.xsl" ?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><sitemap><loc>https://ucuruza.com/wp-sitemap-posts-post-1.xml</loc></sitemap><sitemap><loc>https://ucuruza.com/wp-sitemap-posts-page-1.xml</loc></sitemap><sitemap><loc>https://ucuruza.com/wp-sitemap-taxonomies-category-1.xml</loc></sitemap><sitemap><loc>https://ucuruza.com/wp-sitemap-users-1.xml</loc></sitemap></sitemapindex>