Consider a new SO user with insufficient reputation to make an edit with no approval.
When such users suggest an edit, they can hardly guess that it is possible to keep track of their edit, discover if it is either approved or rejected, and that there may be a comment that describes a reason of the rejection that can help avoid the same situation in future.
The issue is that this tracking information is hidden deep inside a user profile. You need to follow User Page → All Actions → Suggestions (possibly). There is a little chance that an average newcomer even knows what “suggestions” is for, even if they are curious enough to dig into every tab of their own profile.
So I propose to add a notification in the Recent inbox messages area when a suggested edit is either accepted or declined. The notification entry must lead to a review page of a corresponding edit.