Remove the BETA status for torch.linalg (#58043)
Summary:
We are ready to move to the new stage for our `torch.linalg` module, which is stable (or STABLE?).
Ref. https://github.com/pytorch/pytorch/issues/42666
Pull Request resolved: https://github.com/pytorch/pytorch/pull/58043
Reviewed By: ngimel
Differential Revision: D28356172
Pulled By: mruberry
fbshipit-source-id: e2c1effa79b9635b2ef0a820a03a0685105042bd
