Good you were able to get the edit in before the 2hr window closed! For what it's worth, I appreciate when people are transparent about edits. However if you're just correcting a minor typo or fixing some grammar in a way that doesn't alter the original point I think you can safely just go ahead and edit in-place with maybe a "Edit: Oops, changing $foo to $bar. Well spotted, $user!" if you want to be super open about it.

My comments often go through multiple revisions like this in the first ~5 minutes or so. If dang has any ability to see or query these edits I wouldn't be surprised if they discovered my "edits per word" is among the highest in HN :D