Format error and typeof types

[topecongiro]

These two cases are simple enough; I might as well support it instead of panicking.

Also, in a bit extreme case the current implementation can panic against valid Rust code when macro is involved:

macro_rules! foo {
    (typeof($e:expr)) => {}
}

fn main() {
    foo!(typeof(3));
}

Close #4357.

[calebcartwright]

SGTM

[karyon]

Backport done in #4605