Merge pull request #220167 from arcnmx/rtorrent-mainprogram

rtorrent: set meta.mainProgram

pkgs/applications/networking/p2p/jesec-rtorrent/default.nix

···
     license = licenses.gpl2Plus;
     maintainers = with maintainers; [ winter AndersonTorres ];
     platforms = platforms.linux;
+    mainProgram = "rtorrent";
   };
 }

pkgs/applications/networking/p2p/rakshasa-rtorrent/default.nix

···
     license = licenses.gpl2Plus;
     maintainers = with maintainers; [ ebzzry codyopel ];
     platforms = platforms.unix;
+    mainProgram = "rtorrent";
   };
 }