message: Add example and reference to tf.nn.softmax
diff: @@ -2937,6 +2937,13 @@ def softmax(logits, axis=None, name=None, dim=None):
  softmax = tf.exp(logits) / tf.reduce_sum(tf.exp(logits), axis)
  + See: https://en.wikipedia.org/wiki/Softmax_function
  +
  + Example usage:
  + >>> tf.nn.softmax([-1, 0., 1.])
  + <tf.Tensor: id=32, shape=(3,), dtype=float32,
  + numpy=array([0.09003057, 0.24472848, 0.66524094], dtype=float32)>
  +
  Args:
  logits: A non-empty `Tensor`. Must be one of the following types: `half`,
  `float32`, `float64`.
  