Basic SR Content Sequence Attribute fails to reference the Document Relationship Macro Attributes

[sjswerdloff]

Bug description

Basic SR Content Sequence Attribute fails to reference the Document Relationship Macro Attributes.
The Document Relationship Macro contains the (recursive) Content Sequence Attribute, which is kind of the basis of SR.
This may not be readily modeled in the tree (because it implies infinite recursion if one isn't careful about it), but I spent a lot of time scratching my head on this until I went directly to the DICOM Standard. I guess I'd prefer to see one Content Sequence attribute shown within the top level Content Sequence attribute with no further sequence items inside it with some wording that indicates "recursion here, it's turtles all the way down to the leaf attributes".

Steps for reproduction

Expected behavior

Additional context (e.g. screenshots)
See http://dicom.nema.org/medical/dicom/current/output/chtml/part03/sect_C.17.3.html#sect_C.17.3
and compare to "there's no Content Sequence attribute within the Content Sequence attribute".