[FX] Fix python code having spurious newlines from placeholders (#49720)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/49720
Test Plan: Imported from OSS
Reviewed By: zdevito
Differential Revision: D25675825
Pulled By: jamesr66a
fbshipit-source-id: a9028acad9c8feb877fff5cd09aedabed52a3f4b
