Describe the problem that you experienced

In the accessibility best practices, the Case study: Building a custom progress bar does not have any example code.

There is an error in the console which may be associated with the preview, I pasted it below.

Enter the URL of the topic with the problem

https://angular.dev/best-practices/a11y#case-study-building-a-custom-progress-bar

Describe what you were looking for in the documentation

The code associate with case study.

Describe the actions that led you to experience the problem

Opened the webpage.

Describe what you want to experience that would fix the problem

I should be able to see the code snippet associated with the case study.

Add a screenshot if that helps illustrate the problem

If this problem caused an exception or error, please paste it here

TypeError: this.previewsComponents[e] is not a function
    at t.loadPreview (main-FOR4QIEM.js:7:521)
    at r.<anonymous> (chunk-DTDHOMFN.js:6:83987)
    at Generator.next (<anonymous>)
    at chunk-J65QSAYV.js:1:1258
    at new c (polyfills-XXUF43KU.js:2:2235)
    at Mw (chunk-J65QSAYV.js:1:1078)
    at r.renderExample (chunk-DTDHOMFN.js:6:83838)
    at r.<anonymous> (chunk-DTDHOMFN.js:6:97150)
    at Generator.next (<anonymous>)
    at chunk-J65QSAYV.js:1:1258

### If the problem is browser-specific, please specify the device, OS, browser, and version

_No response_

### Provide any additional information here in as much as detail as you can

_No response_