/**
 * Append the Site Reviews rating summary stars, if they exist, to the page title
 * Paste this in your active theme's functions.php file.
 * @param string $title
 * @param int $postId
 * @return string
 */
add_filter('the_title', function ($title, $postId) {
    $postTypes = ['post']; // change this as needed
    if (in_the_loop()
        && in_array(get_post_type($postId), $postTypes)
        && (is_single() || is_home() || is_category() || is_post_type_archive($postTypes))) {
        $shortcode = do_shortcode('[site_reviews_summary assigned_to="post_id" hide="bars,rating" text="<span class=\'num-stars\'>{rating} stars from</span> {num} reviews!"]');
        $shortcode = str_replace(['<div', '/div>'], ['<span', '/span>'], $shortcode); // replace block-level elements
        return sprintf('<span>%s</span>%s', $title, $shortcode);
    }
    return $title;
}, 10, 2);