The demo in the Hierarchical Grid State Persistence topic is throwing an error.

[teodosiah]

Description

The demo in the Hierarchical Grid State Persistence topic is throwing an error in src/app/app.module.ts.

Steps to reproduce

1. Open the Hierarchical Grid State Persistence topic - here.
2. Open the demo in StackBlitz.

Result

Error in src/app/app.module.ts (28:3)
',' expected.

Expected result

Running the sample successfully.

Attachments

Note: I was able to run the sample by making some changes into the app.module.ts file and adding the about.component.
The modified sample could be found here (plus some additional changes, however there are not related to the issue).