lib/unicode_normalize/normalize.rb: Comment clarification. [ci skip]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48290 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-11-06

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48291 b2dd03c8-39d4-4d8f-98ff-823fe69b080e