Added Stepper.Impl.cs (#693)

src/Controls/src/Core/HandlerImpl/Stepper.Impl.cs

@@ -0,0 +1,7 @@
+namespace Microsoft.Maui.Controls
+{
+	public partial class Stepper : IStepper
+	{
+	
+	}
+}

src/Controls/src/Core/Stepper.cs

@@ -1,10 +1,9 @@
 using System;
-using System.ComponentModel;
 using Microsoft.Maui.Controls.Internals;
 
 namespace Microsoft.Maui.Controls
 {
-	public class Stepper : View, IElementConfiguration<Stepper>, IStepper
+	public partial class Stepper : View, IElementConfiguration<Stepper>, IStepper
 	{
 		public static readonly BindableProperty MaximumProperty = BindableProperty.Create(nameof(Maximum), typeof(double), typeof(Stepper), 100.0,
 			validateValue: (bindable, value) => (double)value > ((Stepper)bindable).Minimum,