Use sanitize_key(). sanitize_title_with_dashes() is more than we need. see...

Use sanitize_key(). sanitize_title_with_dashes() is more than we need. see #19815. see [20096], [20097].

git-svn-id: https://core.svn.wordpress.org/trunk@20098 1a063a9b-81f0-0310-95a4-ce76da25c4cd