Minor fix to quantized conv docstring (#35134)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/35134
Test Plan: Imported from OSS
Differential Revision: D20571996
Pulled By: z-a-f
fbshipit-source-id: f5bb12e5779bed24c4e0e2f9e2ce90c8d628bd30
