@FloEdelmann I am confused about how to determine if it is the comment of the root node. So I choose to filter invalid comments by node ranges. If you have better idea, please tell me. Thanks!

<template>
 <!-- this is a comment --> // should report
 <div>
 123
 <!-- this is a comment --> // should not report
 </div>
 <!-- this is a comment --> // should report
</template>

@ota-meshi I updated docs and test cases. Please review it if you have time. Thanks.

Thank you for this PR!

Thanks for your review. I updated code and test cases.