[jiterator] sigmoid_backward: complex (#74948)
Summary:
Follows: https://github.com/pytorch/pytorch/issues/74748
cc kshitij12345!
Pull Request resolved: https://github.com/pytorch/pytorch/pull/74948
Reviewed By: malfet
Differential Revision: D35445949
Pulled By: ngimel
fbshipit-source-id: acd921a210fd15cc78046e37532173162daa38b8
(cherry picked from commit 7883b8d0d06b083e3f11445f3101d2854d9ddc32)
