[docs] Added comment on replicate -> partial for `_NormPartial` (#121976)
Add a version of https://github.com/pytorch/pytorch/pull/121945#discussion_r1525697167 as a comment in the code
Pull Request resolved: https://github.com/pytorch/pytorch/pull/121976
Approved by: https://github.com/wanchaol
ghstack dependencies: #121747, #121869, #121945
