message: Advise batch_normalization with model_to_estimator
diff: @@ -548,9 +548,11 @@ model.compile(optimizer=tf.train.RMSPropOptimizer(0.001),
  estimator = keras.estimator.model_to_estimator(model)
  ```
  -Note: Enable [eager execution](./eager.md) for debugging
  +Note:
  +* Enable [eager execution](./eager.md) for debugging
  [Estimator input functions](./premade_estimators.md#create_input_functions)
  and inspecting data.
  +* Don't use batch normalization or try to finetune batch normalization models with estimators created from `tf.keras.estimator.model_to_estimator`. More details at [#17950](https://github.com/tensorflow/tensorflow/issues/17950)
  ### Multiple GPUs
  