Automated conversion using the untry tool [1] and the following command:
```
$ find -name '*.rs' -type f | xargs untry
```
at the root of the Rust repo.
[1]: https://github.com/japaric/untry
Make AssertRecoverSafe's field public
It's basically the very definition of a newtype, so we might as well
make things easy on people and let them construct and access it
directly.
r? @aturon
Types like `&AssertRecoverSafe<T>` and `Rc<AssertRecoverSafe<T>>` were
mistakenly not considered recover safe, but the point of the assertion wrapper
is that it indeed is! This was caused by an interaction between the
`RecoverSafe` and `NoUnsafeCell` marker traits, and this is updated by adding an
impl of the `NoUnsafeCell` marker trait for `AssertRecoverSafe` to ensure that
it never interacts with the other negative impls of `RecoverSafe`.
cc #30510
Types like `&AssertRecoverSafe<T>` and `Rc<AssertRecoverSafe<T>>` were
mistakenly not considered recover safe, but the point of the assertion wrapper
is that it indeed is! This was caused by an interaction between the
`RecoverSafe` and `NoUnsafeCell` marker traits, and this is updated by adding an
impl of the `NoUnsafeCell` marker trait for `AssertRecoverSafe` to ensure that
it never interacts with the other negative impls of `RecoverSafe`.
cc #30510