Rename WordPress Category Labels

<?php
/**
 * Renames the WordPress category labels.
 *
 * In some Events Manager translations "Event Categories" has been translated
 * exactly the same as the WordPress "Categories", resulting in two identical
 * named meta boxes in the Edit Event Page.
 *
 * @global object $wp_taxonomies The WordPress Taxonomies object.
 * @return void
 */
function stonehenge_em_rename_wp_categories() {
    global $wp_taxonomies;

    $categories = $wp_taxonomies['category'];
    $categories->label                  = 'WP ' . __( 'Categories' );
    $categories->labels->name           = 'WP ' . __( 'Categories' );
    $categories->labels->menu_name      = 'WP ' . __( 'Categories' );
    $categories->labels->singular_name  = 'WP ' . __( 'Category' );
}
add_action( 'init', 'stonehenge_em_rename_wp_categories' );