fix doc

vendor/fakerphp/faker/src/Faker/Extension/Extension.php

@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Faker\Extension;
+
+/**
+ * An extension is the only way to add new functionality to Faker.
+ *
+ * @experimental This interface is experimental and does not fall under our BC promise
+ */
+interface Extension
+{
+}