[optim] take kw-only argument for functional optim APIs (#56185)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/56185
ghstack-source-id: 126670123
Reviewed By: albanD
Differential Revision: D27802169
fbshipit-source-id: f5e1cb2046dcdeecf5f6b0f70892828bf0adb22f
