I saw this post, but I was wondering if perhaps we could add a tab under activity for rejected edits. What I am suggesting if it is unclear is an additional tab that shows rejected edits.
I don't think this justifies filter/tab of its own. Instead, why not just add this extra details in the existing view?
We already have the details when the edit was suggested so tooltip of the approved/rejected will show the time when it occurred and maybe even by whom.