Normally, I would reject this for being "against intent" but it seems like the same person because it is unlikely that someone else would have found the answer within 4 minutes, created an account with the same username (+ a capital) and tried to edit it.
Approve it, if it's a simple addition as in the current case or anything else that is not overly problematic. You might leave an explanatory comment, saying something along the lines of what you wrote here.
If the proposed edit does not make sense as an edit at all, but is rather a reply to a comment, then things are more tricky. Rejecting the edit, and copying over the content in a comment you post yourself is an option. Like:
The following comment was suggested as an edit by an account that appears to be the original poster "[the text]"