tinc module: optionSet -> submodule

nixos/modules/services/networking/tinc.nix

@@ -18,11 +18,7 @@ in
 
       networks = mkOption {
         default = { };
-        type = types.loaOf types.optionSet;
+        type = with types; loaOf (submodule {
-        description = ''
-          Defines the tinc networks which will be started.
-          Each network invokes a different daemon.
-        '';
           options = {
 
             extraConfig = mkOption {
@@ -106,6 +102,12 @@ in
               '';
             };
           };
+        });
+
+        description = ''
+          Defines the tinc networks which will be started.
+          Each network invokes a different daemon.
+        '';
       };
     };