Add @template on RuntimeLoaderinterface (Twig 4)

Do php-stan annotation have an impact on BC promise? 

The interface uses the term "class" already.. i'm guessing it's ok ?

src/RuntimeLoader/RuntimeLoaderInterface.php

@@ -21,7 +21,11 @@ interface RuntimeLoaderInterface
     /**
      * Creates the runtime implementation of a Twig element (filter/function/test).
      *
-     * @return object|null The runtime instance or null if the loader does not know how to create the runtime for this class
+     * @template TRuntime of object
+     *
+     * @param class-string<TRuntime> $class A runtime class name
+     *
+     * @return TRuntime|null The runtime instance or null if the loader does not know how to create the runtime for this class
      */
     public function load(string $class): ?object;
 }