function renderCheckbox(id, label) {
  const checkbox = document.createElement('input');
  checkbox.setAttribute('type', 'checkbox');
  checkbox.setAttribute('id', id);
  const checkboxLabel = document.createElement('label');
  checkboxLabel.textContent = label;
  checkboxLabel.setAttribute('for', id);
  return [checkbox, checkboxLabel];
}
Render a checkbox.
@param {string} id Id to use for the checkbox element.
@param {string} label The label string to use.
@returns {Array<HTMLElement>} A tuple of the checkbox input element, and the
checkbox label element.