[docs] Update sphinx to 3.5.4 (#61601)
Summary:
Sphinx 4.x is out, but it seems that requires many more changes to
adopt. So instead use the latest version of 3.x, which includes
several nice features.
* Add some noindex directives to deal with warnings that would otherwise
be triggered by this change due to conflicts between the docstrings
declaring a function and the autodoc extension declaring the
same function.
* Update distributions.utils.lazy_property to make it look like a
regular property when sphinx autodoc inspects classes.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/61601
Reviewed By: ejguan
Differential Revision: D29801876
Pulled By: albanD
fbshipit-source-id: 544d2434a15ceb77bff236e934dbd8e4dbd9d160
