Administration: Add doing_wp_cron to wp_removable_query_args().

It's a single-use URL parameter that does not need to be passed to canonical URLs in the admin.

Props dlh.
Fixes #49017.

git-svn-id: https://develop.svn.wordpress.org/trunk@47002 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/functions.php

@@ -1162,6 +1162,7 @@ function wp_removable_query_args() {
 		'deactivate',
 		'deleted',
 		'disabled',
+		'doing_wp_cron',
 		'enabled',
 		'error',
 		'hotkeys_highlight_first',