The whole string is escaped with `esc_html()` anyway, so we don't
need to `wp_kses_post()`. This is a better experience for users who
want to use angle brackets in their site title or description.
Does not allow any HTML, adds unit tests.
props BandonRandon, pauldewouters.
fixes#27942.
git-svn-id: https://develop.svn.wordpress.org/trunk@35788 602fd350-edb4-49c9-b593-d223f7449a82