Fix typographical error in torch.triu docstring (#32067)
Summary:
below --> above
Fixes https://github.com/pytorch/pytorch/issues/32032
Pull Request resolved: https://github.com/pytorch/pytorch/pull/32067
Differential Revision: D19355788
Pulled By: zou3519
fbshipit-source-id: dc7a2538a78cd11e72d47ad923ef50599a5a87e2
