* lib/matrix.rb: Fix typo in rdoc

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40382 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2013-04-20

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40383 b2dd03c8-39d4-4d8f-98ff-823fe69b080e