add divider for sub menu

Author: bsatarnejad

app/components/primer/alpha/action_menu/sub_menu_item.rb

@@ -36,6 +36,10 @@ def with_item(**system_arguments, &block)
           @sub_menu.with_item(form_arguments: @form_arguments, **system_arguments, &block)
         end
 
+        def with_divider(**system_arguments, &block)
+          @sub_menu.with_divider(form_arguments: @form_arguments, **system_arguments, &block)
+        end
+
         def with_avatar_item(**system_arguments, &block)
           @sub_menu.with_avatar_item(form_arguments: @form_arguments, **system_arguments, &block)
         end

previews/primer/alpha/action_menu_preview/sub_menus.html.erb

@@ -12,6 +12,7 @@
       <% sub_menu.with_sub_menu_item(label: "Paste from") do |sub_menu| %>
         <% sub_menu.with_item(label: "Current clipboard") %>
         <% sub_menu.with_item(label: "History") %>
+        <% sub_menu.with_divider %>
         <% sub_menu.with_item(label: "Another device") %>
       <% end %>
     <% end %>