Improve inline documentation for `WP_Users_List_Table`.

Props leewillis77 for the initial patch.
Fixes #26564.

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git-svn-id: http://core.svn.wordpress.org/trunk@27154 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Introduce HTML5 gallery support.

When a theme supports HTML5 galleries via add_theme_support( 'html5', 'gallery' ), figure and figcaption will be used instead of definition list markup.

props obenland.
fixes #26697.

Built from https://develop.svn.wordpress.org/trunk@27302


git-svn-id: http://core.svn.wordpress.org/trunk@27155 1a063a9b-81f0-0310-95a4-ce76da25c4cd