A short "hey, I am editing your question because of X Y" is certainly appropriate for the comments section. In this case, the question is clearly about programming, in general. I have made a brief comment pointing to the usage guidelines of the game-design, where it specifically says "not for programming questions about 'design' of features".
Once you feel the point has been made, and assuming it is your comment, there is no need to flag for moderators attention. It is your comment, and as such, you are free to remove it at any time. In this case, it certainly helps to have the editing privledge, which is awarded at 2,000 reputation. Without it, edits are pushed to a review; and in this case, the edit was flat out rejected by the asker.
In this case, I have applied the programming tag, as I feel the question does not specifically apply to graphics-programming, but is certainly against the usage guidelines of game-design. It is possible that the asker may still insist on the original edit, and roll it back. If you are confident that such an edit was appropriate, you should flag the question for moderator attention, as opposed to entering a "rollback war".