Fix the typo in operator name string (#36296)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/36296
When there's no overload name, the operator name string should be "name", instead of "name.".
Test Plan: Imported from OSS
Differential Revision: D20966759
Pulled By: iseeyuan
fbshipit-source-id: b4b31923c7ec5cdca8ac919bd6a84ba51afb6cd1
