Tests: Correct duplicate data set key in sanitize_key() tests.

Follow-up to [52292].

Props Soean.
See #64894.

git-svn-id: https://develop.svn.wordpress.org/trunk@62638 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

tests/phpunit/tests/formatting/sanitizeKey.php

@@ -33,7 +33,7 @@ public function data_sanitize_key() {
 				'key'      => 'howdy,admin',
 				'expected' => 'howdyadmin',
 			),
-			'a lowercase key with commas'    => array(
+			'an uppercase key with commas'   => array(
 				'key'      => 'HOWDY,ADMIN',
 				'expected' => 'howdyadmin',
 			),