Repository get_listing return values need more docs

For example, these options are not all obvious in what they are for:

• 'dynload' => (bool) use dynamic loading,
• 'manage' => (string) link to file manager,
• 'nologin' => (bool) requires login,
• 'nosearch' => (bool) no search link,
• 'upload' => array( // upload manager
• 'name' => (string) label of the form element,
• 'id' => (string) id of the form element
• ),