message: [tf.data] Improve docs for TFRecordDataset and TextLineDataset
diff: @@ -148,7 +148,11 @@ class TextLineDatasetV2(dataset_ops.DatasetSource):
  compression_type=None,
  buffer_size=None,
  num_parallel_reads=None):
  - """Creates a `TextLineDataset`.
  + r"""Creates a `TextLineDataset`.
  +
  + The elements of the dataset will be the lines of the input files, using
  + the newline character '\n' to denote line splits. The newline characters
  + will be stripped off of each element.
  Args:
  filenames: A `tf.string` tensor or `tf.data.Dataset` containing one or
  @@ -306,6 +310,8 @@ class TFRecordDatasetV2(dataset_ops.DatasetV2):
  num_parallel_reads=None):
  """Creates a `TFRecordDataset` to read one or more TFRecord files.
  + Each element of the dataset will contain a single TFRecord.
  +
  Args:
  filenames: A `tf.string` tensor or `tf.data.Dataset` containing one or
  more filenames.
  