nixos: fix some types

nixos/modules/security/pam.nix

@@ -419,7 +419,7 @@ in
     users.motd = mkOption {
       default = null;
       example = "Today is Sweetmorn, the 4th day of The Aftermath in the YOLD 3178.";
-      type = types.nullOr types.string;
+      type = types.nullOr types.lines;
       description = "Message of the day shown to users when they log in.";
     };
 

nixos/modules/security/prey.nix

@@ -24,7 +24,7 @@ in {
       };
 
       deviceKey = mkOption {
-        type = types.string;
+        type = types.str;
         description = ''
           <literal>Device key</literal> obtained by visiting
           <link xlink:href="https://panel.preyproject.com/devices" />
@@ -33,7 +33,7 @@ in {
       };
 
       apiKey = mkOption {
-        type = types.string;
+        type = types.str;
         description = ''
           <literal>API key</literal> obtained from
           <link xlink:href="https://panel.preyproject.com/profile" />.