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/networking/tinc.nix

@@ -87,7 +87,9 @@ in
           };
 
           package = mkOption {
+            type = types.package;
             default = pkgs.tinc_pre;
+            defaultText = "pkgs.tinc_pre";
             description = ''
               The package to use for the tinc daemon's binary.
             '';