Type definition mismatch: isMatchWith customizer function allows truthy/falsy values but TypeScript types restrict to boolean/undefined

Description

There's an inconsistency between Lodash's actual implementation of isMatchWith and its TypeScript type definitions. The current TypeScript definition restricts the customizer function's return type to boolean | undefined, but Lodash's own test cases and implementation suggest it actually accepts any value and treats them as truthy/falsy.

TypeScript Definition

The current type definition in @types/lodash for isMatchWith customizer:

interface IsMatchWithCustomizer {
  (value: any, other: any, indexOrKey: PropertyName, object: object, source: object): boolean | undefined;
}

declare function isMatchWith(
  object: object,
  source: object,
  customizer: IsMatchWithCustomizer
): boolean;

Error Example
When trying to use Lodash's own test utility function with TypeScript:

import { isMatchWith } from 'lodash';

// This is a utility function similar to one used in Lodash's own tests
const stubA = function() {
  return 'a'; // Returns a string, not a boolean
};

const object = { a: 1 };
let actual = isMatchWith(object, { a: 1 }, stubA);

This code produces the following TypeScript error:

Type '() => string' is not assignable to parameter of type 'IsMatchWithCustomizer'.
  Type 'string' is not assignable to type 'boolean | undefined'.ts(2345)

Actual Behavior
Looking at Lodash's own test cases in v5-wip branch, it's clear that the implementation is designed to work with any truthy/falsy values, not just booleans. For example, from Lodash's test:

it('should return a boolean value even when `customizer` does not', () => {
  const object = { a: 1 };
  let actual = isMatchWith(object, { a: 1 }, stubA);
  expect(actual).toBe(true); // passed
  // More tests...
});

If you don't mind, I'd like to redefine that type. If possible, please let me know your contribution guide!