When trying to reply to a comment that is inside a transclusion,
detect if it's transcluded from a subpage or simply wrapped in a
template, and show appropriate error messages.
References:
* VisualEditor ve.dm.Converter#getAboutGroup()
* VisualEditor ve.dm.ModelRegistry#matchElement()
* Parsoid Linter#findEnclosingTemplateName()
Bug: T245694
Change-Id: If3dd1ebbf1d02ee4379c200019bfc3a8ec02325b