e383db7087
As from #76337, precisely https://github.com/flutter/flutter/issues/76337#issuecomment-795486138 and https://github.com/flutter/flutter/issues/76337#issuecomment-2172941109. There is missing documentation with an example on how the [`goldenFileComparator`](https://api.flutter.dev/flutter/flutter_test/goldenFileComparator.html) can be used. This change updates the documentation by providing an additional code snippet to the example that was already stated by the documentation. Follows the effort made by #76337 and https://github.com/flutter/flutter/pull/150343.