message: Fix incorrect docstring of compression type in `TFRecordOptions`
  This fix is a followup to
  In PR 26676, the compression type of "no compression" was incorrectly
  specified as `"NONE"`. This fix addresses the issue and change it to `""`.
diff: @@ -69,7 +69,7 @@ class TFRecordOptions(object):
  Leaving an option as `None` allows C++ to set a reasonable default.
  Args:
  - compression_type: `"GZIP"`, "ZLIB" or `"NONE"`.
  + compression_type: `"GZIP"`, "ZLIB", or `""` (no compression).
  flush_mode: flush mode or `None`, Default: Z_NO_FLUSH.
  input_buffer_size: int or `None`.
  output_buffer_size: int or `None`.
  