Taxonomy: Introduce is_taxonomy_viewable().

This utility function allows for easy detection whether terms for a taxonomy are considered publicly viewable.

Props andizer.
Fixes #44466.


git-svn-id: https://develop.svn.wordpress.org/trunk@43386 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/admin-bar.php

@@ -728,7 +728,7 @@ function wp_admin_bar_edit_menu( $wp_admin_bar ) {
 		} elseif ( 'term' == $current_screen->base
 			&& isset( $tag ) && is_object( $tag ) && ! is_wp_error( $tag )
 			&& ( $tax = get_taxonomy( $tag->taxonomy ) )
-			&& $tax->public ) {
+			&& is_taxonomy_viewable( $tax ) ) {
 			$wp_admin_bar->add_menu(
 				array(
 					'id'    => 'view',