message: Fixed assert_shapes broken code in documentation
  Issue
diff: @@ -1594,10 +1594,10 @@ def assert_shapes_v2(shapes, data=None, summarize=None, message=None,
  ```python
  tf.assert_shapes([
  - (x: ('N', 'Q')),
  - (y: ('N', 'D')),
  - (param: ('Q',)),
  - (scalar: ()),
  + (x, ('N', 'Q')),
  + (y, ('N', 'D')),
  + (param, ('Q',)),
  + (scalar, ()),
  ])
  ```
  