Issue #2152231 follow-up by InternetDevels: Small whitespace clean-up in twig template.

core/modules/system/templates/vertical-tabs.html.twig

@@ -12,4 +12,4 @@
  * @ingroup themeable
  */
 #}
-<div data-vertical-tabs-panes {{ attributes }}>{{ children }}</div>
+<div data-vertical-tabs-panes{{ attributes }}>{{ children }}</div>