Inline documentation cleanup for 4.0 audit.

phpDoc tweaks for methods, properties, and filters added in [29051]:
* `WP_Customize_Control->$active_callback` property
* `WP_Customize_Control::active()` method
* `WP_Customize_Control::active_callback()` method
* `WP_Widget_Area_Customize_Control::active_callback()` method
* `WP_Widget_Form_Customize_Control::active_callback()` method
* 'customize_control_active' filter

Added in [28930]:
* `WP_Customize_Control::input_attrs()` method

See #27993 and #28885.

Built from https://develop.svn.wordpress.org/trunk@29156


git-svn-id: http://core.svn.wordpress.org/trunk@28940 1a063a9b-81f0-0310-95a4-ce76da25c4cd