Attribute not documented
Having run grapfdoc, it produced the expected output with the existing types (objects).
The output says that the Arguments are not documented; any advice on how to document them ?

I found this (Chapter 4.2): https://spec.graphql.org/June2018/#sec-Field-Arguments
"All types in the introspection system provide a description field of type String to allow type designers to publish documentation in addition to capabilities. A GraphQL server may return the description field using Markdown syntax (as specified by CommonMark). Therefore it is recommended that any tool that displays description use a CommonMark‐compliant Markdown renderer."
Is this the field missing (description) ?
Yes.