Eliminate use of `extract()` in `wp_terms_checklist()`.
	
See #22400.

Built from https://develop.svn.wordpress.org/trunk@28410


git-svn-id: http://core.svn.wordpress.org/trunk@28237 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Eliminate use of `extract()` in `Walker_Category_Checklist::start_el()`.
	
See #22400.

Built from https://develop.svn.wordpress.org/trunk@28411


git-svn-id: http://core.svn.wordpress.org/trunk@28238 1a063a9b-81f0-0310-95a4-ce76da25c4cd