Remove deprecated 'no-extra-semicolons' rule from Stylelint (#39400).

git-svn-id: https://svn.redmine.org/redmine/trunk@22392 e93f8b46-1217-0410-a6f0-8f06a7374b81

.stylelintrc

@@ -21,7 +21,6 @@
     "no-duplicate-at-import-rules": true,
     "no-duplicate-selectors": true,
     "no-empty-source": true,
-    "no-extra-semicolons": true,
     "no-invalid-double-slash-comments": true,
   }
 }