Yep, or make a ticket in whatever issue/ticket/work management system you use. Everywhere I’ve worked has always had some kind of “future stuff we’d like to do” project.
But then rather than leaving a non-blocking review, why not leave a blocking review and approve it as soon as the author responds with a link to the ticket or adds it to TODO.md?
If it's important enough to be tracked then I'd want to make sure that it's been filed properly. It's too easy to forget about such a trivial task, especially in a time crunch.
