Add documentation for properties in TensorIterator. (#39792)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39792
I also deleted the dead TensorIterator::remove_dimension,
and reordered some properties so they were more logically
grouped.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Test Plan: Imported from OSS
Differential Revision: D21981739
Pulled By: ezyang
fbshipit-source-id: e7c9ad0233284f7c47322e62035edb704640aafd
