Improve error message foo was previously moved here because it has type bar, which is non-copyable

[Yoric]

I was recently faced with the following error message and it took me a few minutes to figure out what was wrong:

tests/test_manager.rs:93:52: 93:57 error: use of moved value: `value` [E0382]
tests/test_manager.rs:93                                             value: value
                                                                            ^~~~~
tests/test_manager.rs:93:52: 93:57 help: run `rustc --explain E0382` to see a detailed explanation
note: `value` was previously moved here because it has type `foxbox_taxonomy::values::Value`, which is non-copyable

The error was that I was moving a value from inside a loop. I believe that the error message could be improved to

note: This code is executed in a loop or closure, so it needs to move `value` each time
it reaches this point. This would only be possible if the type of `value` was copyable
but `value` has type `foxbox_taxonomy::values::Value`, which is non-copyable.
Perhaps you forgot to call `value.clone()`?

[Mark-Simulacrum]

I believe this is fixed today. We note that the value was moved in a previous iteration of the loop; though we could suggest calling clone() still... opened #42446 to track that.

fn main() {
    let a = String::new();
    loop {
        a;
    }
}

error[E0382]: use of moved value: `a`
 --> test.rs:4:9
  |
4 |         a;
  |         ^ value moved here in previous iteration of loop
  |
  = note: move occurs because `a` has type `std::string::String`, which does not implement the `Copy` trait

error: aborting due to previous error(s)