Reword WPF disclaimer: UWP-specific, not inapplicable

IBackgroundTask/BackgroundTaskBuilder also exist in WAS (different namespace).
Reworded to say this page is UWP-specific guidance, and directed WPF/WinForms
devs to the WAS page with a note about different namespaces/registration.

Co-authored-by: Copilot <[email protected]>

Author: GrantMeStrength

uwp/launch-resume/support-your-app-with-background-tasks.md

@@ -10,7 +10,7 @@ ms.localizationpriority: medium
 # Support your app with background tasks
 
 > [!NOTE]
-> This page covers the UWP background task model (`IBackgroundTask`, `BackgroundTaskBuilder`). This model **does not apply to WPF or Windows Forms apps**. For WPF and Windows Forms apps, see [Background tasks (Windows App SDK)](/windows/apps/windows-app-sdk/applifecycle/background-tasks) (requires MSIX packaging), [Task Scheduler](/windows/win32/taskschd/task-scheduler-start-page) (no packaging required), or [.NET Worker Services](/dotnet/core/extensions/workers) (no packaging required).
+> This page covers the **UWP-specific** background task model (`IBackgroundTask`, `BackgroundTaskBuilder`). For WPF and Windows Forms apps, use the corresponding [Background tasks (Windows App SDK)](/windows/apps/windows-app-sdk/applifecycle/background-tasks) guidance for packaged desktop apps (different namespaces, registration steps, and MSIX packaging requirements), or consider [Task Scheduler](/windows/win32/taskschd/task-scheduler-start-page) (no packaging required) or [.NET Worker Services](/dotnet/core/extensions/workers) (no packaging required).
 
 The topics in this section show you how to make lightweight code run in the background in response to triggers. You can use background tasks to provide functionality when your app is suspended or not running. You can also use background tasks for real-time communication apps like VOIP, mail, and IM.