Add document of functions nn.init.ones_/zeros_ (#23145)
Summary:
Functions `nn.init.ones_` and `nn.init.zeros_` were not documented. As mentioned in https://github.com/pytorch/pytorch/issues/9886
Pull Request resolved: https://github.com/pytorch/pytorch/pull/23145
Differential Revision: D16427108
Pulled By: soumith
fbshipit-source-id: 4fac31e79717a436411ef5e107a829b403e576c9
