Update docs setMenubar (#2845)

Author: reynaldichernando

src/docs/src/UI/setMenubar.md

@@ -16,7 +16,7 @@ puter.ui.setMenubar(options)
 
 #### `options.items` (Array)
 
-An array of menu items. Each item can be a menu or a menu item. Each menu item can have a label, an action, and a submenu.
+An array of menu items. Each item can be a menu or a menu item. Each menu item can have a label, an action, and a submenu. An item can also be the string `-`, which indicates a separator.
 
 #### `options.items.label` (String)
 
@@ -30,6 +30,10 @@ A function to execute when the menu item is clicked.
 
 An array of submenu items.
 
+#### `options.items.disabled` (Boolean)
+
+Indicates whether the menu item is disabled.
+
 ## Examples
 
 ```html;ui-set-menubar
@@ -72,4 +76,4 @@ An array of submenu items.
     </script>
 </body>
 </html>
-```
+```