message: Add an example and reference to relu doc.
diff: op {
  graph_op_name: "Relu"
  summary: "Computes rectified linear: `max(features, 0)`."
  + description: <<END
  +See: https://en.wikipedia.org/wiki/Rectifier_(neural_networks)
  +Example usage:
  +>>> tf.nn.relu([-2., 0., -0., 3.]).numpy()
  +array([ 0., 0., -0., 3.], dtype=float32)
  +END
  }
  