message: Update model_from_yaml and model_from_json docs
diff: @@ -59,8 +59,20 @@ def model_from_config(config, custom_objects=None):
  def model_from_yaml(yaml_string, custom_objects=None):
  """Parses a yaml model configuration file and returns a model instance.
  + Usage:
  +
  + >>> model = tf.keras.Sequential([
  + ... tf.keras.layers.Dense(5, input_shape=(3,)),
  + ... tf.keras.layers.Softmax()])
  + >>> try:
  + ... import yaml
  + ... config = model.to_yaml()
  + ... loaded_model = tf.keras.models.model_from_yaml(config)
  + ... except ImportError:
  + ... pass
  +
  Arguments:
  - yaml_string: YAML string encoding a model configuration.
  + yaml_string: YAML string or open file encoding a model configuration.
  custom_objects: Optional dictionary mapping names
  (strings) to custom classes or functions to be
  considered during deserialization.
  @@ -80,7 +92,15 @@ def model_from_yaml(yaml_string, custom_objects=None):
  @keras_export('keras.models.model_from_json')
  def model_from_json(json_string, custom_objects=None):
  - """Parses a JSON model configuration file and returns a model instance.
  + """Parses a JSON model configuration string and returns a model instance.
  +
  + Usage:
  +
  + >>> model = tf.keras.Sequential([
  + ... tf.keras.layers.Dense(5, input_shape=(3,)),
  + ... tf.keras.layers.Softmax()])
  + >>> config = model.to_json()
  + >>> loaded_model = tf.keras.models.model_from_json(config)
  Arguments:
  json_string: JSON string encoding a model configuration.
  