Docs: Fix broken code syntax in autograd.rst (#69362)
Summary:
The backticks around `nn.Parameters` were not rendered correctly because the word was enclosed in an italics block.
Spotted the issue on https://pytorch.org/docs/stable/notes/autograd.html#locally-disable-grad-doc.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/69362
Reviewed By: zou3519
Differential Revision: D32924093
Pulled By: albanD
fbshipit-source-id: 5a310ac3f3d13a5116f7aa911817b9452eee711d
