It should maintain at most 1 newline between attributes, and none at the end
<label class="block relative">
  <input
    class="absolute inset-0 opacity-0 pointer-events-none peer"
    type="radio"
    name="id"

    id="variant-{{ variant.id }}"
    value="{{ variant.id }}"
    required

    {% unless variant.available %}
      disabled
    {% endunless %}

    {% if product.selected_variant == variant %}
      checked
    {% endif %}
  >
</label>