Improve documentation in dispatcher; remove unnecessary optional (#32533)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/32533
Applies renames based on comments in #32439. I also updated some
other documentation and variable names while I was at it.
Fixes #32435.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Test Plan: Imported from OSS
Differential Revision: D19579854
Pulled By: ezyang
fbshipit-source-id: 85021a92a2a84501f49ee5c16318f81f5df64f8d
