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/web-servers/apache-httpd/default.nix

@@ -429,6 +429,7 @@ in
       package = mkOption {
         type = types.package;
         default = pkgs.apacheHttpd;
+        defaultText = "pkgs.apacheHttpd";
         description = ''
           Overridable attribute of the Apache HTTP Server package to use.
         '';
@@ -437,7 +438,8 @@ in
       configFile = mkOption {
         type = types.path;
         default = confFile;
-        example = literalExample ''pkgs.writeText "httpd.conf" "# my custom config file ...";'';
+        defaultText = "confFile";
+        example = literalExample ''pkgs.writeText "httpd.conf" "# my custom config file ..."'';
         description = ''
           Override the configuration file used by Apache. By default,
           NixOS generates one automatically.