Add check for TechDocs annotation on entity

Signed-off-by: Andre Wanlin <awanlin@rapidrtc.com>

plugins/techdocs/src/Router.tsx

@@ -25,6 +25,9 @@ import { MissingAnnotationEmptyState } from '@backstage/core-components';
 
 const TECHDOCS_ANNOTATION = 'backstage.io/techdocs-ref';
 
+export const isTechDocsAvailable = (entity: Entity) =>
+  Boolean(entity?.metadata?.annotations?.[TECHDOCS_ANNOTATION]);
+
 export const Router = () => {
   return (
     <Routes>

plugins/techdocs/src/index.ts

@@ -44,4 +44,4 @@ export {
   TechDocsReaderPage,
 } from './plugin';
 export * from './reader';
-export { EmbeddedDocsRouter, Router } from './Router';
+export { EmbeddedDocsRouter, Router, isTechDocsAvailable } from './Router';