moduleGroup = (children, modules) => {
	let size = 0;
	/** @type {Record<string, number>} */
	const sizes = {};
	for (const module of children) {
		size += module.size;
		for (const key of Object.keys(module.sizes)) {
			sizes[key] = (sizes[key] || 0) + module.sizes[key];
		}
	}
	return {
		size,
		sizes
	};
}
@template {{ size: number, sizes: Record<string, number> }} T
@param {Children<T>[]} children children
@param {KnownStatsModule[]} modules modules
@returns {{ size: number, sizes: Record<string, number>}} size and sizes