Docgen user manual generation fails for OCL examples

[wobrschalek]

This 2 chapters fail to generate:

[2022.11.23::16:23:06]	ERR: illegal operation signature: (cref_name()) for OCL query "cref_name()" on How Do I Create Transclusions with OCL Queries?[_18_0_2_bec02f9_1444944942233_724594_73192]
[2022.11.23::16:23:06]	ERR: illegal operation signature: (cref_doc()) for OCL query "cref_doc()" on How Do I Create Transclusions with OCL Queries?[_18_0_2_bec02f9_1444944942233_724594_73192]