Cleanup documentation (#19584)
Summary:
Stack from [ghstack](https://github.com/ezyang/ghstack):
* **#19584 [jit] Cleanup documentation**
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19584
Pulled By: driazati
Differential Revision: D15104801
fbshipit-source-id: 87391fd62ee92b615e680469f8bd9a1ac654be7e
