message: Fix typo in data-loader documentation
diff: @@ -15,7 +15,7 @@ DataLoader can be used in GraphQL Modules with an easy setup. You can use them a
  export const UserModule = new GraphQLModule({
  providers: [
  {
  - provide: MY_DATA_LOADER,
  + provide: USER_DATA_LOADER,
  useFactory: () => new DataLoader(keys => myBatchGetUsers(keys));
  }
  ],
  @@ -38,7 +38,7 @@ DataLoader can be used in GraphQL Modules with an easy setup. You can use them a
  export const UserModule = new GraphQLModule({
  providers: [
  {
  - provide: MY_DATA_LOADER,
  + provide: USER_DATA_LOADER,
  useFactory: InjectFunction(MyExternalDataProvider)(
  (myExternalDataProvider) => new DataLoader(
  keys => myExternalDataProvider.getData(keys)
  @@ -67,7 +67,7 @@ You can see how to generate DataLoader in GraphQLModules using factory functions
  providers: [
  {
  scope: ProviderScope.Session
  - provide: MY_DATA_LOADER,
  + provide: USER_DATA_LOADER,
  useFactory:
  InjectFunction(ModuleSessionInfo)(
  // Use Dependency Injection to get ModuleSessionInfo to access network session
  