nixos/*: escape config reference in examples and descriptions

nixos/modules/services/games/factorio.nix

@@ -75,8 +75,8 @@ in
         description = ''
           The name of the savegame that will be used by the server.
 
-          When not present in ${stateDir}/saves, a new map with default
-          settings will be generated before starting the service.
+          When not present in /var/lib/''${config.services.factorio.stateDirName}/saves,
+          a new map with default settings will be generated before starting the service.
         '';
       };
       # TODO Add more individual settings as nixos-options?

nixos/modules/services/web-servers/uwsgi.nix

@@ -121,7 +121,7 @@ in {
               moin = {
                 type = "normal";
                 pythonPackages = self: with self; [ moinmoin ];
-                socket = "${config.services.uwsgi.runDir}/uwsgi.sock";
+                socket = "''${config.services.uwsgi.runDir}/uwsgi.sock";
               };
             };
           }