emacs: retire myself from maintainers

I added myself because I integrated Macport support but I don't really feel qualified to maintain the rest of emacs.

The Macport integration has also been working without major issues ever since it was introduced.

I still left bread crumbs in case there's an issue with macport specifically but
I don't want to be pinged on generic Emacs issues/PRs.

pkgs/applications/editors/emacs/sources.nix

@@ -53,10 +53,10 @@ let
       maintainers = with lib.maintainers; [
         AndersonTorres
         adisbladis
-        atemu
         jwiegley
         lovek323
         matthewbauer
+        # atemu for issues relating to Macport
       ];
       platforms = {
         "mainline" = lib.platforms.all;