show toc in custom taxonomy page

I Built a custom taxonomy in my theme with this code :

<?php
function build_taxonomies(){
	$type_labels = array(
        'name' => __( 'project cat', 'ehsanma' ),
        'singular_name' => __( 'project cat', 'ehsanma' ),
        'search_items' =>  __( 'project cat', 'ehsanma' ),
        'popular_items' => __( 'project cat', 'ehsanma' ),
        'all_items' => __( 'project cat', 'ehsanma' ),
        'parent_item' => __( 'project cat', 'ehsanma' ),
        'parent_item_colon' => __( 'project cat:', 'ehsanma' ),
        'edit_item' => __( 'project cat', 'ehsanma' ), 
        'update_item' => __( 'project cat', 'ehsanma' ),
        'add_new_item' => __( 'project cat', 'ehsanma' ),
        'new_item_name' => __( 'project cat', 'ehsanma' ),
        'menu_name' => __( 'project cat', 'ehsanma' )
    );
	
	register_taxonomy(
	    'project-cat', 
	    array( 'project' ), 
	    array(
	        'hierarchical' => true, 
	        'labels' => $type_labels,
	        'show_ui' => true,
	        'query_var' => true,
			'rewrite' => array('slug' => __('project-cat', 'ehsanma'))
	    )
	);
}
add_action( 'init', 'build_taxonomies', 0 );
?>

in options page of TOC plugin I checked this option : ” Show the table of contents for description on the custom taxonomy pages.”

but when I add shortcode to my taxonomy description its not showing the table of contents.

need any changed on my code to active toc for my taxonomy pages?