message: Update doc example for tf.Variable.scatter_nd_update()
diff: @@ -911,9 +911,8 @@ class Variable(six.with_metaclass(VariableMetaclass, trackable.Trackable)):
  v = tf.Variable([1, 2, 3, 4, 5, 6, 7, 8])
  indices = tf.constant([[4], [3], [1] ,[7]])
  updates = tf.constant([9, 10, 11, 12])
  - op = v.scatter_nd_assign(indices, updates)
  - with tf.compat.v1.Session() as sess:
  - print sess.run(op)
  + v.scatter_nd_update(indices, updates)
  + print(v)
  ```
  The resulting update to v would look like this:
  