Issue #3159535 by jackniu, jungle, longwave: Fix "finegrained|perfoming|fieldeset" typos in core

core/misc/cspell/dictionary.txt

core/modules/editor/js/editor.admin.es6.js

core/modules/system/templates/fieldset.html.twig

...em/tests/src/Functional/UpdateSystem/UpdateScriptTest.php

...ami/themes/umami/templates/classy/form/fieldset.html.twig

...Drupal/KernelTests/Core/Theme/ConfirmClassyCopiesTest.php

core/themes/bartik/templates/classy/form/fieldset.html.twig

core/themes/classy/templates/form/fieldset.html.twig

core/themes/seven/templates/classy/form/fieldset.html.twig

...es/media-library/fieldset--media-library-widget.html.twig

core/themes/stable/templates/form/fieldset.html.twig

core/themes/stable9/templates/form/fieldset.html.twig