Relax rule: Only enforce const in destructuring when all variables are constant

[feross]

When we added prefer-const, we kept the default setting which is quite strict when there's a bunch of variables being assigned at once in destructuring. For example, this is considered an error:

let { a, b } = obj
a = a + 1

This is because b is never mutated. So it wants us to rewrite the code like this:

let { a } = obj
const { b } = obj
a = a + 1

When there are many variables being assigned at once through destructuring, or when variables are being switched from mutated vs. not mutated, this causes a lot of churn. I'd rather err on the side of leniency here and just allow the whole block to be let if any of the variables are mutated.

Only when we can affirmatively say that all variables are const, should the whole thing be forced to be const. So, I'll enable the {"destructing": "all"} option. https://eslint.org/docs/rules/prefer-const#destructuring

Feedback welcome.

[feross]

Released as 13.0.1 since I think this rule is likely to cause folks a lot of trouble.

Specifically, it wanted me to split up this component's props into a const and let because one of the props (style) is mutated:

const Loader = props => {
  let {
    center,
    class: className,
    label = 'Loading',
    style,
    ...rest
  } = props

  if (center) {
    style = {
      blah: 1
    }
  }

This is too much work. I'd rather just keep this whole destructing assignment using let.