Reference autocompletion inserts `&` in wrong place in macros

I could have sworn we have a ticket for this, but I couldn't find it.
```rust
// some extra text

enum Foo { Bar }

fn foo(foo: &Foo) {}

fn test() {
    println!("{}", foo(Foo::Ba<|>))
}
```
using the `&Bar` completion here inserts the ampersand in the wrong place.