Adds arctanh, arcsinh aliases, simplifies arc* alias dispatch (#43762)
Summary:
Adds two more "missing" NumPy aliases: arctanh and arcsinh, and simplifies the dispatch of other arc* aliases.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/43762
Reviewed By: ngimel
Differential Revision: D23396370
Pulled By: mruberry
fbshipit-source-id: 43eb0c62536615fed221d460c1dec289526fb23c
