Issue #1838114 by ry5n, swentel, sun: change node form’s vertical tabs into details elements.

core/includes/form.inc

core/modules/book/book.module

core/modules/comment/comment.module

core/modules/menu/menu.module

core/modules/node/lib/Drupal/node/NodeFormController.php

.../modules/node/lib/Drupal/node/Plugin/Core/Entity/Node.php

...s/options/lib/Drupal/options/Tests/OptionsWidgetsTest.php

core/modules/path/path.module

core/modules/system/system.theme.css

core/themes/seven/style.css