docs: code examples running successfully
## Description
This pull request solves both #72921 and an identical, unreported issue in another part of the documentation.
## Documentation Changes Preview
- ### Typo in https://pytorch.org/docs/stable/generated/torch.no_grad.html#codecell0:
#### Before:
#### After:
- ### Typo in https://pytorch.org/docs/stable/generated/torch.autograd.set_grad_enabled.html?highlight=set_grad_enabled#codecell0:
#### Before:
#### After:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/74044
Approved by: https://github.com/albanD
