Add rdoc about IO#read(length). [ruby-core:29161]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27604 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Add rdoc about IO#read(length). [ruby-core:29161]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27604 b2dd03c8-39d4-4d8f-98ff-823fe69b080e