* lib/irb.rb:  Fix typo


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39736 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2013-03-13

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39737 b2dd03c8-39d4-4d8f-98ff-823fe69b080e