javadocs for Tensor, IValue, Module (#26149)
Summary:
At the moment it includes https://github.com/pytorch/pytorch/pull/26219 changes. That PR is landing at the moment, afterwards this PR will contain only javadocs.
Applied all dreiss comments from previous version.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/26149
Differential Revision: D17490720
Pulled By: IvanKobzarev
fbshipit-source-id: f340dee660d5ffe40c96b43af9312c09f85a000b
