un.rb: nodoc setup

* lib/un.rb (setup): nodoc for internal use method.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41798 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/un.rb

@@ -32,6 +32,7 @@ module FileUtils
   @fileutils_output = $stdout
 end
 
+# :nodoc:
 def setup(options = "", *long_options)
   opt_hash = {}
   argv = []