Return an array from a render function to write multiple templates (11ty.js)

[zachleat]

Per #3629 and #4146 it would be kinda neat to (as an alternative to pagination?) return an array of results from a render function to write multiple templates!

export default function (data) {
	return [
		`<p>First</p>`,
		`<p>Second</p>`,
	];
};

Might need some additional permalink translation too (instead of just appending a count to the path) so maybe also:

export default function (data) {
	return [
		[`<p>First</p>`, "/path1/"],
		[`<p>Second</p>`, "/path2/"]
	];
};

[zachleat]

Would be a higher order solution to #4036 #4046 and maybe even #3991