Please ensure that your pull request fulfills these requirements:

• The pull request is being made against the master branch
• Tests for the changes have been added (for bug fixes / features)

What is the purpose of this pull request? (bug fix, enhancement, new feature,...)

Rather bug fix.

What changes did you make?

As for server.listen, server.close (both for HTTP and HTTPS servers, as returned by union) takes an optional callback which is called on completion or error. This patch adds argument forwarding for close.

Provide some example code that this change will affect, if applicable:

	const server = createServer({
		root: path.join(__dirname, '..', 'files'),
	});

	await new Promise((resolve) => server.listen(port, resolve));
	
	...

	await new Promise((resolve) => server.close(resolve as any));

Is there anything you'd like reviewers to focus on?

Well there's no tests, should I somehow write one?

As a side note, HttpServer.prototype.close forwards the return value of this.server.close, i.e. this. But HttpServer.prototype.listen does not. I think it should too.

Please provide testing instructions, if applicable:

Above code.