It was found that in several places in the HTML API and its supporting files, the wrong form of type annotation was used for optional parameters. Instead of using `?type`, this patch uses `type|type-of-default-value` instead, noting where important if the parameter is optional, and if so, what its default value is. Developed in https://github.com/WordPress/wordpress-develop/pull/7031 Discussed in https://core.trac.wordpress.org/ticket/61399 Props dmsnell, jonsurrell. See #61399. Built from https://develop.svn.wordpress.org/trunk@58742 git-svn-id: http://core.svn.wordpress.org/trunk@58144 1a063a9b-81f0-0310-95a4-ce76da25c4cd