Misc doc updates / fixes (#24371)
Summary:
This is a bunch of changes to the docs for stylistic changes,
correctness, and updates to the new script API / recent TorchScript
changes (i.e. namedtuple)
For reviewers, ping me to see a link of the rendered output.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/24371
Pulled By: driazati
Differential Revision: D16832417
fbshipit-source-id: a28e748cf1b590964ca0ae2dfb5d8259c766a203
