An anonymous user made the following edit to the answer I gave to this question

The edit is merely a "thank you" note. So it doesn't seem to be a "valid" edit and more something that should have been added as a comment.

The user who asked the question has a rep of 1 now and thus can't add comments I believe, which might be why she opted for an edit.

However rejecting the edit might appear impolite or ungrateful. Any recommendations?