`torch.linalg.lstsq`: forward/backward AD support (#65054)
Summary:
As per title.
cc ezyang albanD zou3519 gqchen pearu nikitaved soulitzer Lezcano Varal7 jianyuh mruberry walterddr IvanYashchuk xwang233
Pull Request resolved: https://github.com/pytorch/pytorch/pull/65054
Reviewed By: zou3519
Differential Revision: D31729468
Pulled By: albanD
fbshipit-source-id: ab7df824bc80128e7f64f6444c7a4baa4786c161
