Recommend using Windows Runtime type Geolocator instead of GeoCoordinateWatcher

We need to add a note to the doc https://docs.microsoft.com/en-us/dotnet/api/system.device.location.geocoordinatewatcher?view=netframework-4.8 saying apps recommended to use Geolocator class https://docs.microsoft.com/en-us/uwp/api/windows.devices.geolocation.geolocator for location services instead of using GeoCoordinateWatcher. The reason is GeoCoordinateWatcher is using old Windows Location interfaces which proceeded by the Windows Runtime type Geolocator.