What does “Convert overload list to single signature” mean?

I am still learning some basics of javascript programming (and programming in general).

In my Angular Firebase project, I get the following typescript error (or rather proposed change in visual studio code, i.e. the lightbulb icon):

Convert overload list to single signature

It is referring to the following code:

  updateUser(user: UserDocument): Observable<any> {
    const ref = doc(this.firestore, 'users', user.uid);
    return from(updateDoc(ref, { ...user }));
  }

When I convert it, it appears like this:

  updateUser(...args: [user: UserDocument]): Observable<any> {
    const ref = doc(this.firestore, 'users', user.uid);
    return from(updateDoc(ref, { ...user }));
  }

But now instead it is complaining Remove unused declaration of args and also it complains about the last bid { ...user } giving another lightbulb Import user from module "rxfire/auth"

I would appreciate it very much if someone gave a short explanation of what is going on?

Thank you!

EDIT: here are two screenshots just for extra clarity