[Gradient Compression] Remove the extra comma after "bucket" in PowerSGD hook signatures (#50197)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/50197
Remove the extra comma after "bucket".
ghstack-source-id: 119513484
Test Plan: waitforbuildbot
Reviewed By: rohan-varma
Differential Revision: D25823117
fbshipit-source-id: acf048f7cb732c23cba3a81ccce1e70f6b9f4299
