WordPress Add Taxonomy (Category or Tag) before post title in RSS Feeds

WordPress-Add-Taxonomy-to-RSS-Feeds.php

<?php

/**
 * Prepend taxonomy name before feed title for Articles
 * This will work for any custom post type or custom taxonomy
 */
function add_feed_item_title($content)
{
    global $wp_query;
    
    // Remember we only want to do this for post type 'post'
    if ($wp_query->post->post_type != 'post') return;

    $postid = $wp_query->post->ID;
    $post_title = $wp_query->post->post_title;
    
    $category = wp_get_post_terms($postid, 'category');
    $content = $category[0]->name ." : ". htmlspecialchars($post_title);
    
    return $content;
}
add_filter('the_title_rss', 'add_feed_item_title');