In the initial configuration the enablePHP config option is present. In the following abstracted example the commonConfig doesn't include it anymore.
Previous PRs #88505 and #284906 added the enablePHP config option to the commonConfig. @aanderse commented in https://github.com/NixOS/nixpkgs/pull/88505#issuecomment-632575200 the usage of enablePHP shouldn't be encouraged, `services.phpfpm` should be preferred whenever possible. So we remove the enablePHP config from theses examples.