The example for updating a Theme resource is incomplete.

The example for updating the theme resources at runtime is incomplete. Clearing mergedDictionaries breaks scenarios where other merged resources are being used, such as styles defined in a satellite assembly.

ICollection mergedDictionaries = Application.Current.Resources.MergedDictionaries;
if (mergedDictionaries != null)
{
mergedDictionaries.Clear(); <--- This clears 'all' merged entries, not just the previous theme dictionary.
mergedDictionaries.Add(new DarkTheme());
}

---
#### Document Details

⚠ *Do not edit this section. It is required for learn.microsoft.com ➟ GitHub issue linking.*

* ID: 04d29bb3-0ea9-e42a-d6d2-cf338baca362
* Version Independent ID: 04d29bb3-0ea9-e42a-d6d2-cf338baca362
* Content: [Theme an app - .NET MAUI](https://learn.microsoft.com/en-us/dotnet/maui/user-interface/theming?view=net-maui-7.0)
* Content Source: [docs/user-interface/theming.md](https://github.com/dotnet/docs-maui/blob/main/docs/user-interface/theming.md)
* Product: **dotnet-mobile**
* Technology: **dotnet-maui**
* GitHub Login: @davidbritch
* Microsoft Alias: **dabritch**

Open docs/user-interface/theming.md and find the runtime theme-resource update example linked in the issue. Review how the example handles Application.Current.Resources.MergedDictionaries; done means the documented update no longer removes unrelated merged resources, including resources from a satellite assembly.

Written by the indexing model from the issue text.