message: updated batch_jacobian example that was throwing
  updated batch_jacobian example that was throwing a warning
diff: @@ -1112,7 +1112,7 @@ class GradientTape(object):
  ```python
  with tf.GradientTape() as g:
  - x = tf.constant([[1, 2], [3, 4]], dtype=tf.float32)
  + x = tf.constant([[1., 2.], [3., 4.]], dtype=tf.float32)
  g.watch(x)
  y = x * x
  batch_jacobian = g.batch_jacobian(y, x)
  