[sort-type-union-intersection-members] Can null and undefined be sorted separately from other keywords?

[jgeurts]

Sometimes null gets lost with other types when it's sorted with the rest of the keyword types. Moving null and undefined to their own group would allow them to be sorted independently to other types.

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I have read the FAQ and my problem is not listed.

Repro

{
  "rules": {
    "@typescript-eslint/sort-type-union-intersection-members": "error"
  }
}

Current Behavior

function foo(input: number | null | string | undefined) { ... }

Proposed Behavior

function foo(input: number | string | null | undefined) { ... }

Versions

package	version
@typescript-eslint/eslint-plugin	4.12.0
@typescript-eslint/parser	4.12.0
TypeScript	4.1.3
ESLint	7.17.0
node	12.20.1

[bradzacher]

technically this is a breaking change, but because we have just released it, and we release every week (and I know adoption is usually slow), I'm okay with it.