Add more `std` prelude items to `crate::prelude`

Add more `std` prelude items to `crate::prelude`

New rustc beta now warns on duplicate imports when one of the
imports is from a wildcard import or the default prelude. Thus, for
simplicity, we need to make our `crate::prelude` mostly identical
to the `std` one, allowing us to always simply use the
`crate::prelude` and let it decide if we need to import anything.