nixos/services.saslauthd: remove `with lib;`

nixos/modules/services/system/saslauthd.nix

···
   pkgs,
   ...
 }:
-
-with lib;
-
 let
 
   cfg = config.services.saslauthd;
···
 
     services.saslauthd = {
 
-      enable = mkEnableOption "saslauthd, the Cyrus SASL authentication daemon";
+      enable = lib.mkEnableOption "saslauthd, the Cyrus SASL authentication daemon";
 
-      package = mkPackageOption pkgs [ "cyrus_sasl" "bin" ] { };
+      package = lib.mkPackageOption pkgs [ "cyrus_sasl" "bin" ] { };
 
-      mechanism = mkOption {
-        type = types.str;
+      mechanism = lib.mkOption {
+        type = lib.types.str;
         default = "pam";
         description = "Auth mechanism to use";
       };
 
-      config = mkOption {
-        type = types.lines;
+      config = lib.mkOption {
+        type = lib.types.lines;
         default = "";
         description = "Configuration to use for Cyrus SASL authentication daemon.";
       };
···
 
   ###### implementation
 
-  config = mkIf cfg.enable {
+  config = lib.mkIf cfg.enable {
 
     systemd.services.saslauthd = {
       description = "Cyrus SASL authentication daemon";