For your consideration,
In the interest of using the RAML to fully document an interface it is often necessary to to provide more detailed information to document special use cases or additional table or lists of coded values for an implementer. This additional information would not be appropriate in the description node as it could be far too verbose.
Currently tools such as Anypoint Designer/Exchange and raml2html render the documentation in the order of
The new notes? node should render at the end of these structures and behave the same way as the description node.
The documentation? node is not viable as that is only supported at the root of the RAML document.