message: Fix typos in contrib.estimator.extenders.py
diff: @@ -27,7 +27,7 @@ _VALID_METRIC_FN_ARGS = set(['features', 'labels', 'predictions', 'config'])
  def add_metrics(estimator, metric_fn):
  - """Creates new ${tf.estimator.Esitmator} which has given metrics.
  + """Creates new ${tf.estimator.Estimator} which has given metrics.
  Example:
  @@ -54,7 +54,7 @@ def add_metrics(estimator, metric_fn):
  ```
  Args:
  - estimator: A ${tf.estimator.Esitmator} object.
  + estimator: A ${tf.estimator.Estimator} object.
  metric_fn: A function which should obey the following signature:
  - Args: can only have following four arguments in any order:
  * predictions: Predictions `Tensor` or dict of `Tensor` created by given
  