Feature: Add assist to unwrap tuple declarations
> Implement #12923 for only tuples.
>
> Does not implement unwrapping for structs, as mentioned in the issue.
Add assist to unwrap tuples declarations to separate declarations.
```rust
fn main() {
$0let (foo, bar, baz) = (1.0, "example", String::new())
}
```
becomes:
```rust
fn main() {
let foo = 1.0;
let bar = "example";
let baz = String::new();
}
```
## Changelog
### Feature
- Added assist to unwrap tuple declarations.