Added missing alpha and async

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

docs/backend-system/building-backends/08-migrating.md

@@ -330,7 +330,7 @@ depends on the appropriate extension point and interacts with it.
 
 ```ts title="packages/backend/src/index.ts"
 /* highlight-add-start */
-import { catalogProcessingExtensionPoint } from '@backstage/plugin-catalog-node';
+import { catalogProcessingExtensionPoint } from '@backstage/plugin-catalog-node/alpha';
 import { createBackendModule } from '@backstage/backend-plugin-api';
 /* highlight-add-end */
 
@@ -344,7 +344,7 @@ const catalogModuleCustomExtensions = createBackendModule({
         catalog: catalogProcessingExtensionPoint,
         // ... and other dependencies as needed
       },
-      init({ catalog /* ..., other dependencies */ }) {
+      async init({ catalog /* ..., other dependencies */ }) {
         // Here you have the opportunity to interact with the extension
         // point before the plugin itself gets instantiated
         catalog.addEntityProvider(new MyEntityProvider()); // just an example
@@ -399,7 +399,7 @@ depends on the appropriate extension point and interacts with it.
 
 ```ts title="packages/backend/src/index.ts"
 /* highlight-add-start */
-import { eventsExtensionPoint } from '@backstage/plugin-events-node';
+import { eventsExtensionPoint } from '@backstage/plugin-events-node/alpha';
 import { createBackendModule } from '@backstage/backend-plugin-api';
 /* highlight-add-end */
 
@@ -413,7 +413,7 @@ const eventsModuleCustomExtensions = createBackendModule({
         events: eventsExtensionPoint,
         // ... and other dependencies as needed
       },
-      init({ events /* ..., other dependencies */ }) {
+      async init({ events /* ..., other dependencies */ }) {
         // Here you have the opportunity to interact with the extension
         // point before the plugin itself gets instantiated
         events.addSubscribers(new MySubscriber()); // just an example
@@ -464,7 +464,7 @@ depends on the appropriate extension point and interacts with it.
 
 ```ts title="packages/backend/src/index.ts"
 /* highlight-add-start */
-import { scaffolderActionsExtensionPoint } from '@backstage/plugin-scaffolder-node';
+import { scaffolderActionsExtensionPoint } from '@backstage/plugin-scaffolder-node/alpha';
 import { createBackendModule } from '@backstage/backend-plugin-api';
 /* highlight-add-end */
 
@@ -478,7 +478,7 @@ const scaffolderModuleCustomExtensions = createBackendModule({
         scaffolder: scaffolderActionsExtensionPoint,
         // ... and other dependencies as needed
       },
-      init({ scaffolder /* ..., other dependencies */ }) {
+      async init({ scaffolder /* ..., other dependencies */ }) {
         // Here you have the opportunity to interact with the extension
         // point before the plugin itself gets instantiated
         scaffolder.addActions(new MyAction()); // just an example