[FIX] Remove ClassLoader mention

The ClassLoader component was removed in Symfony 4.0.

Author: Hipio

components/intl.rst

@@ -48,17 +48,6 @@ replace the intl classes:
 
 Composer automatically exposes these classes in the global namespace.
 
-If you don't use Composer but the
-:doc:`Symfony ClassLoader component </components/class_loader>`,
-you need to expose them manually by adding the following lines to your autoload
-code::
-
-    if (!function_exists('intl_is_failure')) {
-        require '/path/to/Icu/Resources/stubs/functions.php';
-
-        $loader->registerPrefixFallback('/path/to/Icu/Resources/stubs');
-    }
-
 Writing and Reading Resource Bundles
 ------------------------------------