valid-title should allow functions

[JoshuaKGoldberg]

As of vitest-dev/vitest#3493 -> vitest-dev/vitest#3497, Vitest describes & similar can take in function names. I think the valid-title rule should by default no longer complain if a function name is provided.

Before:

import { describe } from "vitest"

function isBodyWithReplies() { /* ... */ }

describe(isBodyWithReplies, () => {
	//   ~~~~~~~~~~~~~~~~~~ Test title must be a string
	// ...
})

After:

import { describe } from "vitest"

function isBodyWithReplies() { /* ... */ }

describe(isBodyWithReplies, () => {
	//   OK
	// ...
});

describe(1234567890, () => {
	//   ~~~~~~~~~~ Test title must be a function or string
	// ...
});

I'd be happy to send a PR for this! ❤️

[veritem]

a PR would be much appreciated as always.