doc fix `nn.Module`: docstring should come after class variable (#72912)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/72862
Pull Request resolved: https://github.com/pytorch/pytorch/pull/72912
Reviewed By: cpuhrsch
Differential Revision: D34286017
Pulled By: jbschlosser
fbshipit-source-id: d172f7600e7f66c30187996ee42c72bf273643cc
(cherry picked from commit d9f9b5b4180fb1554eaca675a20661b979da2234)
