message: Fix TensorBoard tutorial links to the wrong MNIST tutorial example code
diff: @@ -83,7 +83,7 @@ data than you need, though. Instead, consider running the merged summary op
  every `n` steps.
  The code example below is a modification of the
  -@{$layers$simple MNIST tutorial},
  +[simple MNIST tutorial](https://github.com/tensorflow/tensorflow/blob/master/tensorflow/examples/tutorials/mnist/mnist.py),
  in which we have added some summary ops, and run them every ten steps. If you
  run this and then launch `tensorboard --logdir=/tmp/tensorflow/mnist`, you'll be able
  to visualize statistics, such as how the weights or accuracy varied during
  