Fixed documentation on imports of the plugin-techdocs-backend

Signed-off-by: Floww <Floww@users.noreply.github.com>

docs/features/techdocs/getting-started.md

@@ -213,7 +213,7 @@ const backend = createBackend();
 // Other plugins...
 
 /* highlight-add-start */
-backend.add(import('@backstage/plugin-search-backend-module-catalog/alpha'));
+backend.add(import('@backstage/plugin-techdocs-backend/alpha'));
 /* highlight-add-end */
 
 backend.start();

docs/features/techdocs/how-to-guides.md

@@ -759,11 +759,11 @@ const techdocsCustomerBuildStrategy = createBackendModule({
 // Other plugins...
 
 /* highlight-add-start */
-backend.add(import('@backstage/plugin-search-backend-module-catalog/alpha'));
-backend.add();
+backend.add(import('@backstage/plugin-techdocs-backend/alpha'));
+backend.add(techdocsCustomerBuildStrategy());
 /* highlight-add-end */
 
-backend.start(techdocsCustomerBuildStrategy());
+backend.start();
 ```
 
 > Note: You may need to add the `@backstage/plugin-techdocs-node` package to your backend `package.json` if it's not been imported already.