docs(angular): use an actual schematic in example of converting it to an nx generator (#14716)

docs/shared/guides/nx-devkit-angular-devkit.md

@@ -130,7 +130,7 @@ Then, you might need to register it in the `collections.json`:
 
 ```typescript
 export const libraryGenerator = wrapAngularDevkitSchematic(
-  '@nrwl/angular',
+  '@schematics/angular',
   'library'
 );