Issue #2221755 by grom358, ianthomas_uk: Remove uses of deprecated Element functions.

core/includes/authorize.inc

core/includes/common.inc

core/includes/form.inc

core/includes/menu.inc

core/includes/theme.inc

core/lib/Drupal/Component/Utility/SortArray.php

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

core/lib/Drupal/Core/Render/Element.php

core/modules/aggregator/aggregator.theme.inc

core/modules/book/book.admin.inc

core/modules/book/book.module

core/modules/book/lib/Drupal/book/Form/BookAdminEditForm.php

...s/ckeditor/lib/Drupal/ckeditor/Plugin/Editor/CKEditor.php

core/modules/comment/comment.module

...modules/contact/lib/Drupal/contact/MessageViewBuilder.php

...modules/content_translation/content_translation.admin.inc

...upal/content_translation/ContentTranslationController.php

core/modules/edit/lib/Drupal/edit/Form/EditFieldForm.php

core/modules/editor/editor.module

core/modules/entity_reference/entity_reference.module