[ruby/rubygems] Appease the linter again

ruby/rubygems@92f35e9684

Author: JasonLunn

test/rubygems/test_gem_ext_builder.rb

@@ -250,7 +250,7 @@ def test_build_multiple_extensions
       assert_path_exist File.join @spec.gem_dir, "lib", "a", "b.rb"
     end
   end
-  
+
   def test_build_extensions_none
     use_ui @ui do
       @builder.build_extensions