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/phpfpm.nix

@@ -36,7 +36,9 @@ in {
       };
 
       phpPackage = mkOption {
+        type = types.package;
         default = pkgs.php;
+        defaultText = "pkgs.php";
         description = ''
           The PHP package to use for running the FPM service.
         '';