message: Update docstring for CategoricalAccuracy.
diff: @@ -760,6 +760,9 @@ class CategoricalAccuracy(MeanMetricWrapper):
  ultimately returned as `categorical accuracy`: an idempotent operation that
  simply divides `total` by `count`.
  + `y_pred` and `y_true` should be passed in as vectors of probabilities, rather
  + than as labels. If necessary, use `tf.one_hot` to expand `y_true` as a vector.
  +
  If `sample_weight` is `None`, weights default to 1.
  Use `sample_weight` of 0 to mask values.
  """
  