Issue #2282125 by joshi.rohit100, mtift: Fixed Remove instances of '@return self'.

core/lib/Drupal/Core/Config/ConfigInstallerInterface.php

core/lib/Drupal/Core/Config/ConfigModuleOverridesEvent.php

...lib/Drupal/Core/Entity/Display/EntityDisplayInterface.php

core/lib/Drupal/Core/Entity/EntityInterface.php

core/lib/Drupal/Core/File/MimeType/MimeTypeGuesser.php

core/lib/Drupal/Core/Image/ImageFactory.php

core/lib/Drupal/Core/Page/HeadElement.php

core/lib/Drupal/Core/Plugin/DefaultPluginBag.php

core/lib/Drupal/Core/TypedData/ListDataDefinition.php

core/modules/image/src/ImageEffectInterface.php

core/modules/image/src/ImageStyleInterface.php

core/modules/system/src/DateFormatInterface.php

core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php