message: Docstring: train_step and make_train_function are public
diff: @@ -475,7 +475,7 @@ class Model(network.Network, version_utils.ModelVersionSelector):
  """The logic for one training step.
  This method can be overridden to support custom training logic.
  - This method is called by `Model._make_train_function`.
  + This method is called by `Model.make_train_function`.
  This method should contain the mathemetical logic for one step of training.
  This typically includes the forward pass, loss calculation, backpropagation,
  @@ -483,7 +483,7 @@ class Model(network.Network, version_utils.ModelVersionSelector):
  Configuration details for *how* this logic is run (e.g. `tf.function` and
  `tf.distribute.Strategy` settings), should be left to
  - `Model._make_train_function`, which can also be overridden.
  + `Model.make_train_function`, which can also be overridden.
  Arguments:
  data: A nested structure of `Tensor`s.
  @@ -525,7 +525,7 @@ class Model(network.Network, version_utils.ModelVersionSelector):
  Typically, this method directly controls `tf.function` and
  `tf.distribute.Strategy` settings, and delegates the actual training
  - logic to `Model._train_step`.
  + logic to `Model.train_step`.
  This function is cached the first time `Model.fit` or
  `Model.train_on_batch` is called. The cache is cleared whenever
  