       when non-existing atoms are found by the tokenizer.
       Defaults to `false`.
 
-  ## Macro.to_string/2
+  ## `Macro.to_string/2`
 
   The opposite of converting a string to its quoted form is
   `Macro.to_string/2`, which converts a quoted form to a string/binary


  Accepts `relative_to` as an argument to tell where the file is located.
  The return value is the same as that of `load_file/2`. If the file was already
  required/loaded, `require_file` doesn't do anything and returns `nil`.

  Notice that if `require_file` is invoked by different processes concurrently,
  the first process to invoke `require_file` acquires a lock and the remaining
  ones will block until the file is available. I.e., if `require_file` is called
  N times with a given file, it will be loaded only once. The first process to
  call `require_file` will get the list of loaded modules, others will get `nil`.

  Check `load_file/2` if you want a file to be loaded multiple times. See also
  `unload_files/1`

  ## Examples

  If the code is already loaded, it returns `nil`:

      Code.require_file("eex_test.exs", "../eex/test") #=> nil

  If the code is not loaded yet, it returns the same as `load_file/2`:

      Code.require_file("eex_test.exs", "../eex/test") |> List.first
      #=> {EExTest.Compiled, <<70, 79, 82, 49, ...>>}

  """


  ## Examples

      Code.append_path(".")
      #=> true

      Code.append_path("/does_not_exist")
      #=> {:error, :bad_directory}

  """
  def append_path(path) do
