sample/pty/script.rb: Specify frozen_string_literal: true.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57529 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

sample/pty/script.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'pty'
 
 if ARGV.size == 0 then
@@ -34,4 +35,3 @@ PTY.spawn("/bin/csh") do |r_pty,w_pty,pid|
 end
 
 system "stty echo -raw lnext ^v"
-