message: bring back not found
diff: @@ -19,6 +19,7 @@ import { useOutlet } from 'react-router';
  import { useParams } from 'react-router-dom';
  import { useAsync } from 'react-use';
  import { techdocsApiRef } from '../../api';
  +import { TechDocsNotFound } from './TechDocsNotFound';
  import { TechDocsEntityMetadata, TechDocsMetadata } from '../../types';
  import { EntityName } from '@backstage/catalog-model';
  import { useApi } from '@backstage/core-plugin-api';
  @@ -64,6 +65,10 @@ export const TechDocsPage = ({ children }: Props) => {
  setDocumentReady(true);
  }, [setDocumentReady]);
  + if (entityMetadataError) {
  + return <TechDocsNotFound errorMessage={entityMetadataError.message} />;
  + }
  +
  if (!children) return outlet;
  return (
  