docs: OO.ui.CapsuleMultiSelectWidget: Config options
docs: OO.ui.CapsuleMultiSelectWidget: Config options

* Add links to methods
* Set default for option
* Mark as required

Change-Id: I1a75e9aa24ccbe8773b5d20ea6ec23bf48bbf420

wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui