remove unused `type: ignore` directives (#60006)
Summary:
During development it is common practice to put `type: ignore` comments on lines that are correct, but `mypy` doesn't recognize this. This often stems from the fact, that the used `mypy` version wasn't able to handle the used pattern.
With every new release `mypy` gets better at handling complex code. In addition to fix all the previously accepted but now failing patterns, we should also revisit all `type: ignore` comments to see if they are still needed or not. Fortunately, we don't need to do it manually: by adding `warn_unused_ignores = True` to the configuration, `mypy` will error out in case it encounters an `type: ignore` that is no longer needed.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/60006
Reviewed By: jbschlosser, malfet
Differential Revision: D29133237
Pulled By: albanD
fbshipit-source-id: 41e82edc5cd5affa7ccedad044b59b94dad4425a
