Issue #2909185 by longwave, donquixote, andypost, andregp, pounard, jibran, martin107, kostyashupenko, catch, znerol: Replace ContainerAwareEventDispatcher with Symfony EventDispatcher

Issue #3436255 by mondrake, longwave: Fix return typehinting for Compiler and EventSubscriber related classes

Issue #2507237 by dimitriskr, twistor, longwave, smustgrave: Replace ReflectionClass::implementsInterface() with is_subclass_of()

Issue #3222251 by bbrala, longwave: [November 8, 2021] Replace all isset constructs with the null coalescing operator

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2237101 by Mile23, cordoval, YesCT, dawehner, tim.plunkett: clean up for Core/DependencyInjection CompilerPasses

Issue #2546782 by joshi.rohit100, zniki.ru, dawehner: Rename \Drupal\Core\DependencyInjection\Compiler\RegisterKernelListenersPass to RegisterEventSubscribersPass

Issue #1392754 by tss, justAChris, jhodgdon: Comply with new documentation standards for @file for namespaced class files

Issue #1614186 by RobLoach, tim.plunkett, msonnabaum, Crell, jhodgdon, Niklas Fiekas: Update coding standards for using 'native' PHP classes like stdClass in namespaced code.

Issue #1824400 by gapple, katbailey: Rename the service tag 'kernel.event_subscriber()' to just 'event_subscriber()'.

Conflicts:

	core/lib/Drupal/Core/DependencyInjection/ContainerBuilder.php