Common interface for documentation nodes.
make System.doc.doc_node(name): Construct new document node object.name: Name of node.children: Child nodes of the current node.description: Description of current node.name: Full name of current nodeadd(child): Add node to current node's list of children.child: Child node to add.output(formatter): Outputs documentation for the given node.formatter: The System.doc.outputters object to use.