WindowServer: Add API to change virtual desktop settings

This also adds the ability to query how many virtual desktops are
set up, and for the Taskbar to be notified when the active virtual
desktop has changed.

Userland/Services/WindowServer/Window.cpp

@@ -1204,4 +1204,5 @@ String Window::computed_title() const
         return String::formatted("{} (Not responding)", title);
     return title;
 }
+
 }