message: Improve docstring for tf.data.Dataset.shuffle()
diff: @@ -733,6 +733,11 @@ class Dataset(object):
  def shuffle(self, buffer_size, seed=None, reshuffle_each_iteration=None):
  """Randomly shuffles the elements of this dataset.
  + This dataset fills a buffer with `buffer_size` elements, then randomly
  + samples elements from this buffer, replacing the selected elements with new
  + elements. For perfect shuffling, a buffer size greater than or equal to the
  + full size of the dataset is required.
  +
  Args:
  buffer_size: A `tf.int64` scalar `tf.Tensor`, representing the
  number of elements from this dataset from which the new
  