Beef up documentation on Dispatcher.h, reorder methods for clarity. (#33838)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/33838
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Test Plan: Imported from OSS
Differential Revision: D20227875
Pulled By: ezyang
fbshipit-source-id: 319855b1f0fa436f9ed5256d2106b07f20e6b833
