fix ENV.to_a rdoc example by @benolee [fix GH-288]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40322 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

hash.c

@@ -2926,7 +2926,7 @@ env_inspect(void)
  *
  * Converts the environment variables into an array of names and value arrays.
  *
- *   ENV.to_a # => [["TERM" => "xterm-color"], ["SHELL" => "/bin/bash"], ...]
+ *   ENV.to_a # => [["TERM", "xterm-color"], ["SHELL", "/bin/bash"], ...]
  *
  */
 static VALUE