message: Added ```python for usage examples
diff: @@ -974,12 +974,14 @@ class GradientTape(object):
  Example usage:
  + ```python
  with tf.GradientTape() as g:
  x = tf.constant([1.0, 2.0])
  g.watch(x)
  y = x * x
  jacobian = g.jacobian(y, x)
  # jacobian value is [[2., 0.], [0., 4.]]
  + ```
  Args:
  target: Tensor to be differentiated.
  @@ -1082,12 +1084,14 @@ class GradientTape(object):
  result in the jacobian computation given the independence assumption.
  Example usage:
  + ```python
  with tf.GradientTape() as g:
  x = tf.constant([[1, 2], [3, 4]], dtype=tf.float32)
  g.watch(x)
  y = x * x
  batch_jacobian = g.batch_jacobian(y, x)
  # batch_jacobian is [[[2, 0], [0, 4]], [[6, 0], [0, 8]]]
  + ```
  Args:
  target: A tensor with rank 2 or higher and with shape [b, y1, ..., y_n].
  