Add missing 'type', 'defaultText' and 'literalExample' in module definitions

- add missing types in module definitions
- add missing 'defaultText' in module definitions
- wrap example with 'literalExample' where necessary in module definitions

nixos/modules/config/ldap.nix

@@ -57,6 +57,7 @@ in
     users.ldap = {
 
       enable = mkOption {
+        type = types.bool;
         default = false;
         description = "Whether to enable authentication against an LDAP server.";
       };