Merge branch '6.1' into 6.2

* 6.1:
  [Serializer] Added missing __call to TraceableNormalizer and TraceableSerializer
  update docblock to not expose the internal class
  [FrameworkBundle][TwigBundle] Fix registering html-sanitizer services
  [DependencyInjection] remove static cache from `ServiceSubscriberTrait`

Author: derrabus

Resources/config/html_sanitizer.php

@@ -22,7 +22,7 @@
 
         ->set('html_sanitizer.sanitizer.default', HtmlSanitizer::class)
             ->args([service('html_sanitizer.config.default')])
-            ->tag('html_sanitizer', ['name' => 'default'])
+            ->tag('html_sanitizer', ['sanitizer' => 'default'])
 
         ->alias('html_sanitizer', 'html_sanitizer.sanitizer.default')
         ->alias(HtmlSanitizerInterface::class, 'html_sanitizer')

Test/KernelTestCase.php

@@ -12,6 +12,7 @@
 namespace Symfony\Bundle\FrameworkBundle\Test;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\DependencyInjection\Container;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException;
 use Symfony\Component\HttpKernel\KernelInterface;
@@ -83,7 +84,7 @@ protected static function bootKernel(array $options = []): KernelInterface
      *
      * Using this method is the best way to get a container from your test code.
      *
-     * @return TestContainer
+     * @return Container
      */
     protected static function getContainer(): ContainerInterface
     {