"Edit Content" Button in Dashboard should automatically open Widgets Panel

[scottsousa]

See https://core.trac.wordpress.org/ticket/28032

Examples:

• autofocus[panel]=widgets
• autofocus[section]=colors
• autofocus[control]=blogname

[scottsousa]

Core has not yet stabilized the autofocus function so we'll hold off until a future release. We can use the following code snippet to implement this: add_query_arg( 'autofocus[panel]', 'widgets', wp_customize_url() ).