Ruby » Ruby master

extension.rdoc: fix rb_get_kwargs [ci skip]

• doc/extension.rdoc: [DOC] optional keyword arguments are
  defaulted to Qundef. ignored keys are kept in the hash but a
  new Hash is not created. [ruby-dev:49893] [Bug #13004]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56980 b2dd03c8-39d4-4d8f-98ff-823fe69b080e