Add arrayIncludes()

[ifiokjr]

Description

This adds an improved arrayIncludes function which acts as a type guard.

import {arrayIncludes} from 'ts-extras';

const values = ['a', 'b', 'c'] as const;
declare const valueToCheck: unknown;
let value: typeof values[number];

if (arrayIncludes(values, valueToCheck)) {
  // Now we know that the value is of type `typeof values[number]`.
  value = valueToCheck
} else {
  // @ts-expect-error
  value = valueToCheck
}