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/services/backup/bacula.nix

@@ -207,7 +207,7 @@ in {
         description = ''
           Extra configuration to be passed in Client directive.
         '';
-        example = literalExample ''
+        example = ''
           Maximum Concurrent Jobs = 20;
           Heartbeat Interval = 30;
         '';
@@ -218,7 +218,7 @@ in {
         description = ''
           Extra configuration to be passed in Messages directive.
         '';
-        example = literalExample ''
+        example = ''
           console = all
         '';
       };