+ var mdoc: nullable MDoc is writable
+
+ # The documentation associated to the entity or their main nested entity.
+ #
+ # MPackage fall-back to their root MGroup
+ # MGroup fall-back to their default_mmodule
+ # Other entities do not fall-back
+ #
+ # One may use `MDoc::original_mentity` to retrieve the original
+ # source of the documentation.
+ fun mdoc_or_fallback: nullable MDoc do return mdoc