Document the default arguments for `register_sidebars()` in the hash notation style.

Props coffee2code.
See #28298.

Built from https://develop.svn.wordpress.org/trunk@30769


git-svn-id: http://core.svn.wordpress.org/trunk@30759 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Document the default arguments for `the_widget()` in the hash notation style.

Props coffee2code.
See #28298.

Built from https://develop.svn.wordpress.org/trunk@30770


git-svn-id: http://core.svn.wordpress.org/trunk@30760 1a063a9b-81f0-0310-95a4-ce76da25c4cd