Remove in-memory scalars and add comments (#20038)
Summary:
This takes care of some outstanding review comments for https://github.com/pytorch/pytorch/pull/16196/
Specifically:
1. Add comment about kind
2. Add comment about GraphPy
3. Remove ONNX version comment
4. Remove scalar_dict from SummaryWriter and all history functions
cc lanpa ezyang
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20038
Reviewed By: natalialunova
Differential Revision: D15177257
Pulled By: orionr
fbshipit-source-id: 218aa799d8b7dbb58f422a331236bba4959347de
