message: ObjectTypeDefinitionNode for object extractor
diff: @@ -13,7 +13,7 @@ import { Blackboard } from "./Blackboard";
  import {
  DocumentNode,
  - TypeDefinitionNode,
  + ObjectTypeDefinitionNode,
  NonNullTypeNode,
  NamedTypeNode,
  ListTypeNode,
  @@ -27,7 +27,7 @@ const visitorEnter = (
  state: State,
  blackboard: Blackboard
  ) => ({
  - ObjectTypeDefinition: (node: TypeDefinitionNode) => {
  + ObjectTypeDefinition: (node: ObjectTypeDefinitionNode) => {
  // Skip non-custom types
  if (node.name.value === "Query" || node.name.value === "Mutation") {
  return;
  @@ -63,7 +63,7 @@ const visitorEnter = (
  });
  const visitorLeave = (state: State) => ({
  - ObjectTypeDefinition: (_node: TypeDefinitionNode) => {
  + ObjectTypeDefinition: (_node: ObjectTypeDefinitionNode) => {
  state.currentType = undefined;
  },
  FieldDefinition: (_node: FieldDefinitionNode) => {
  