message: Fix a typo in documentation of ModelCheckpoint:
  tf.saved_model.SavedOptions -> tf.saved_model.SaveOptions
diff: @@ -1191,7 +1191,7 @@ class ModelCheckpoint(Callback):
  could reflect as little as 1 batch, since the metrics get reset every
  epoch). Defaults to `'epoch'`.
  options: Optional `tf.train.CheckpointOptions` object if
  - `save_weights_only` is true or optional `tf.saved_model.SavedOptions`
  + `save_weights_only` is true or optional `tf.saved_model.SaveOptions`
  object if `save_weights_only` is false.
  **kwargs: Additional arguments for backwards compatibility. Possible key
  is `period`.
  