fix rubocop error

Author: andi

spec/simple_navigation/item_adapter_spec.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+class ModifiedHash < Hash; end
+
 RSpec.describe SimpleNavigation::ItemAdapter do
   let(:item_adapter) { described_class.new(item) }
 

spec/spec_helper.rb

@@ -151,5 +151,3 @@ def setup_items(container) # rubocop:disable Metrics/AbcSize
     end
   end
 end
-
-class ModifiedHash < Hash; end