docs: public List<NodeTypeDefinition> readAllNodeTypes() {
          CachedNode nodeTypes = nodeTypesNode();
          List<NodeTypeDefinition> defns = new ArrayList<NodeTypeDefinition>();
          for (ChildReference ref : nodeTypes.getChildReferences(system)) {
              CachedNode nodeType = system.getNode(ref);
              defns.add(readNodeTypeDefinition(nodeType));
          }
          return defns;
      }