Renaming variables declared by destructuring causes destructuring pattern to become invalid

```rust
struct Foo {
    i: i32,
}

fn foo(foo: Foo) {
    let Foo { i } = foo;
    let _ = i<|>;
}
```
renaming `i` to `bar` here gives:
```rust
struct Foo {
    i: i32,
}

fn foo(foo: Foo) {
    let Foo { bar } = foo;
    let _ = bar;
}
```
which is incorrect as `Foo` has no `bar` field. Instead it should be `Foo { i: bar }`.