message: Update layers.py
  fixed a typo in the documentation
diff: @@ -2613,7 +2613,7 @@ def spatial_softmax(features,
  Read more here:
  "Learning visual feature spaces for robotic manipulation with
  - deep spatial autoencoders." Finn et. al, http://arxiv.org/abs/1509.06113.
  + deep spatial autoencoders." Finn et al., http://arxiv.org/abs/1509.06113.
  Args:
  features: A `Tensor` of size [batch_size, W, H, num_channels]; the
  