setItemComplete(id, completed) {
		const listItem = qs(`[data-id="${id}"]`);

		if (!listItem) {
			return;
		}

		listItem.className = completed ? 'completed' : '';

		// In case it was toggled from an event and not by clicking the checkbox
		qs('input', listItem).checked = completed;
	}
Render an item as either completed or not.

@param {!number} id Item ID
@param {!boolean} completed True if the item is completed