Rule proposal: Disallow unions with `unknown` or `any`

[fregante]

Description

From what I understand, T | unknown and T | any resolve to just unknown and any respectively, so I don't think they're particularly useful.

Fail

type MaybeNumber = number | unknown;

function isNumber(value: number | any): value is number {
	return typeof value === 'number';
}

Pass

type MaybeNumber = unknown;

function isNumber(value: any): value is number {
	return typeof value === 'number';
}

[bradzacher]

We already have such a rule - no-redundant-type-constituents

https://typescript-eslint.io/rules/no-redundant-type-constituents/

[fregante]

Indeed I had already asked for it but the search had no results with "unknown commenter:@me" 😩

#3926

I remember we had already discussed this but I was starting to question my sanity.