fix typo [ci skip]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46316 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
fix usage

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46317 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
fix a typo [ci skip]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46318 b2dd03c8-39d4-4d8f-98ff-823fe69b080e