Add option for spread rest siblings exclusion for noUnusedVariables rule

[EvHaus]

A common pattern to omit keys from an object is to spread it like so:

const car = {model: "Model S", brand: "Tesla", year: 2019};

// Remove model & year keys from the object
const {model, year, ...other} = car;

// Use the new object
formatBrand(other);

This is effectively equivalent to:

const car = {model: "Model S", brand: "Tesla", year: 2019};

delete car.model;
delete car.year;

// Use the new object
formatBrand(car);

Except that it's an immutable way of doing it, and doesn't violate the performance.noDelete rule.

Unfortunately, the correctness/noUnusedVariables rule currently (and correctly) flags this syntax as a violation, as the model and year variables now become unused.

I'm wondering if maybe there could be an option on the correctness/noUnusedVariables rule to ignoreRestSiblings or something like that? ESLint has it here: https://eslint.org/docs/latest/rules/no-unused-vars#ignorerestsiblings

[Conaclos]

Thanks for bringing this to light! I think this could be the default behavior without any option. We already skip some cases like unused parameters preceding a used parameter. It's kind of related.

[chungweileong94]

Yeah, this one feels like a deal breaker to me. The only way to work around this is to label it with _.

[Conaclos]

I opened #1910 to address this.