minor docs fix to adam (#936)
minor docs fix to adam (#936)

Removed note about re-scaling the lr with Adam.

I believe this is a legacy of the old way LR+Adam was handled and that the docs weren't updated when the code was updated.

Pushing a PR because this is confusing to read now.  :)  (Unless I'm wrong!)
tensorflow/tensor2tensor,vthorsteinsson/tensor2tensor,vthorsteinsson/tensor2tensor,tensorflow/tensor2tensor,tensorflow/tensor2tensor,vthorsteinsson/tensor2tensor,vthorsteinsson/tensor2tensor,tensorflow/tensor2tensor,tensorflow/tensor2tensor