Improve return type of getProvidedServices in ServiceProviderInterface

Author: andersonamuller

ServiceProviderInterface.php

@@ -39,7 +39,7 @@ public function has(string $id): bool;
      *  * ['foo' => '?'] means the container provides service name "foo" of unspecified type
      *  * ['bar' => '?Bar\Baz'] means the container provides a service "bar" of type Bar\Baz|null
      *
-     * @return string[] The provided service types, keyed by service names
+     * @return array<string, string> The provided service types, keyed by service names
      */
     public function getProvidedServices(): array;
 }