message: Add a note to `model_to_estimator` docs about weighted metrics.
diff: @@ -169,6 +169,11 @@ def model_to_estimator_v2(keras_model=None,
  estimator.train(input_fn, steps=1)
  ```
  + Note: We do not support creating weighted metrics in Keras and converting them
  + to weighted metrics in the Estimator API using `model_to_estimator`.
  + You will have to create these metrics directly on the estimator spec using the
  + `add_metrics` function.
  +
  To customize the estimator `eval_metric_ops` names, you can pass in the
  `metric_names_map` dictionary mapping the keras model output metric names
  to the custom names as follows:
  