Fixes Document.Body and Document.DocumentElement return types (#1772)
Fixes Document.Body and Document.DocumentElement return types (#1772)

* [1516] Document.Body should return an HTMLBodyElement
* [1771] Document.BodyElement should be an HTMLHtmlBodyElement

AndreyZM/Bridge,bridgedotnet/Bridge,bridgedotnet/Bridge,AndreyZM/Bridge,bridgedotnet/Bridge,bridgedotnet/Bridge,AndreyZM/Bridge,AndreyZM/Bridge