message: Fix a typo in xla.estimator_model_fn docstring
diff: @@ -606,8 +606,8 @@ class _ModelFnWrapper(object):
  def estimator_model_fn(target_model_fn=None):
  """estimator_model_fn decorates a model_fn to be compiled for execution.
  - Currently only it only works with `TPUEstimator`. If you need to use it with
  - base `Estimator`, please add `tf.enable_resource_variables()` at beginning of
  + Currently it only works with `TPUEstimator`. If you need to use it with base
  + `Estimator`, please add `tf.enable_resource_variables()` at the beginning of
  your program.
  Example 1, decorating model_fn:
  