Themes: Search the description too.

props dd32.
fixes #26309.
Built from https://develop.svn.wordpress.org/trunk@26480


git-svn-id: http://core.svn.wordpress.org/trunk@26377 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Themes: Add type="search" to search. fixes #26331.
Built from https://develop.svn.wordpress.org/trunk@26481


git-svn-id: http://core.svn.wordpress.org/trunk@26378 1a063a9b-81f0-0310-95a4-ce76da25c4cd