The <cxxUnionNested> element within <cxxUnion> contains <cxxUnionNestedDetail> which gives details of nested members of this c++ union
<cxxUnionNested> contains one mandatory <cxxUnionNestedDetail> element and no attributes.
<cxxUnionNested>
<cxxUnionNestedDetail>
<cxxUnionNestedStruct href="struct_comms.xml#struct_comms_package">CommsFW::TCFLegacyMessagePacker::TUnion::TLegacyPackage</cxxUnionNestedStruct>
<cxxUnionNestedStruct href="struct_comms.xml#struct_comms_package">CommsFW::TCFLegacyMessagePacker::TUnion::TPackage</cxxUnionNestedStruct>
</cxxUnionNestedDetail>
</cxxUnionNested>
cxxUnionNestedDetail no-topic-nesting,
(cxxUnionNestedDetail then (no-topic-nesting, ))