Improvement for collection type.

[cesaryuan]

Hi, thanks for your excellent work, it helps me so much. And I fell there may be still something to be improved. For example, https://github.com/cy-gh/DOpus_ScriptingHelper/blob/624626aa79b7a81373a7765bebc76935339fd80b/_DOpusDefinitions.d.ts#L6845 It may be better to create a collection generic type, such as readonly selected: DOpusCollection<DOpusItem>;