[Feature Request] Code Actions: Generate setters that return `&mut Self`

Hello,

I think it will be extremely useful to auto-generate setters that return a mutable reference to self.

We could use them to chain together setter operations, and simplify our code.

I specifically use them to construct objects, or to only partially modify objects.

Also, chaining together operations is pretty comfy.

For a struct such as this:

struct Student {
    age: usize,
    books: usize,
}

We would use it to construct objects as:

  let me = *Student::new()
    .set_age(30)
    .set_books(300);

Or only partially modify objects as:

 let me = &mut students[i];
 me.set_age(40);

The current code actions only generate setters that don't return anything.

To make this chaining feature work, the setters obviously need to return a &mut Self. As in,

pub fn set_age(&mut self, age: usize) -> &mut Self {
  self.age = age;
  self
}

I think this feature would be extremely useful.

Thanks!

No implementation files or tests are named in the issue. Locate the code-action entry point for generating setters and its existing tests, then verify how generated setters are expected to return a mutable reference and support chaining. Done means the requested setter behavior is implemented with coverage for construction and partial mutation.