Update user_preferences.module

modules/user_preferences/user_preferences.module

@@ -48,7 +48,7 @@ function user_preferences_node_links_alter(array &$links, NodeInterface $node, a
     $is_book = isset($node->book['bid']);
 
     if(!$is_admin){
-        $can_add_child_page = $user->hasPermission('Add content and child pages to books and manage their hierarchies');
+        $can_add_child_page = $user->hasPermission('add content to books');
     }
 
 	if ($context['view_mode'] == 'full' && node_is_page($node)) {