[docs] Change fut.wait() to torch.jit._wait(fut) in jit overview docs (#32336)
Summary:
It looks like the jit Future does not have a `wait()` anymore and this throws an error when trying to run this code.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/32336
Differential Revision: D19559922
Pulled By: rohan-varma
fbshipit-source-id: a5aa67990595e98e0682a20cf5aced17c2ae85bb
