"0 elided lifetimes" is still confusing

``` rust
struct S<'a> {
    field: &'a i32,
}
fn f(a: &S, b: i32) -> &i32 {
    panic!();
}
```

```
test.rs:4:24: 4:28 help: this function's return type contains a borrowed value,
but the signature does not say whether it is borrowed from one of `a`'s 2 elided lifetimes
or one of `b`'s 0 elided lifetimes
```

See #30086 for a similar issue which has been fixed.
