[FX][docs] Indent forward (#51802)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51802
lol
Test Plan: Imported from OSS
Reviewed By: zou3519
Differential Revision: D26284311
Pulled By: jamesr66a
fbshipit-source-id: 0d303d8c99131abb8d97e0acd0ac2d810e1e950c
