title: Custom taxonomy template is not selected by default
body: <p>I have register a custom post type <code>faq</code> and a taxonomy for <code>faq</code> named <code>cat_faq</code>. I created a template named <code>taxonomy-cat_faq.php</code>, but it is not selected by default. It always displays a 404 page. I could not understand why this happens so? I read out the <a href="https://developer.wordpress.org/files/2014/10/template-hierarchy.png" rel="nofollow">Template Hierarchy</a> and worked as follows but failed to find out the error. I have attached the code below</p>
  
  <pre><code>add_action('init', 'register_faq');
  function register_faq(){
      $post_type = 'faq';
      $label = array(
          'name'          =&gt; _x('FAQ', 'FAQ', 'faq'),
          'singular_name' =&gt; _x('FAQ', 'FAQ', 'faq'),
          'menu_name'     =&gt; _x('FAQ', 'admin menu', 'faq')
          );
      $args = array(
          'labels'        =&gt; $label,
          'public'    =&gt; true,
          'rewrite'   =&gt; array('slug' =&gt; 'faq'),
          'capability'    =&gt; 'post',
          'supports'      =&gt; array('title', 'editor', 'thumbnail'),
      );
      register_post_type($post_type, $args);
  }
  
  // create taxonomies for the post type "faq"
  add_action( 'init', 'create_faq_taxonomies', 0 );
  function create_faq_taxonomies() {
      $labels = array(
          'name'              =&gt; _x( 'FAQ', 'taxonomy general name' ),
          'singular_name'     =&gt; _x( 'FAQ', 'taxonomy singular name' ),
          'search_items'      =&gt; __( 'Search FAQ' ),
          'edit_item'         =&gt; __( 'Edit FAQ' ),
          'update_item'       =&gt; __( 'Update FAQ' ),
          'add_new_item'      =&gt; __( 'Add New FAQ' ),
          'new_item_name'     =&gt; __( 'New FAQ' ),
          'menu_name'         =&gt; __( 'Category FAQ' ),
      );
  
      $args = array(
          'hierarchical'      =&gt; true,
          'labels'            =&gt; $labels,
          'show_ui'           =&gt; true,
          'show_admin_column' =&gt; true,
          'query_var'         =&gt; true,
          'rewrite'           =&gt; array( 'slug' =&gt; 'cat_faq' ),
      );
  
      register_taxonomy( 'cat_faq', array( 'faq' ), $args );
  }   
  </code></pre>