Merge pull request tensorflow#14930 from mrshu/mrshu-softmax_cross_entropy

softmax_cross_entropy: Improve docstring

Author: caisq

tensorflow/python/ops/losses/losses_impl.py

@@ -652,7 +652,7 @@ def softmax_cross_entropy(
 
  Args:
  onehot_labels: `[batch_size, num_classes]` target one-hot-encoded labels.
- logits: [batch_size, num_classes] logits outputs of the network .
+ logits: `[batch_size, num_classes]` logits outputs of the network .
  weights: Optional `Tensor` whose rank is either 0, or rank 1 and is
  broadcastable to the loss which is a `Tensor` of shape `[batch_size]`.
  label_smoothing: If greater than 0 then smooth the labels.