Added Parameter attribute to constructor parameters (#6516)

Xamarin.Forms.Core/Items/ItemsLayout.cs

@@ -4,7 +4,7 @@
 	{
 		public ItemsLayoutOrientation Orientation { get; }
 
-		protected ItemsLayout(ItemsLayoutOrientation orientation)
+		protected ItemsLayout([Parameter("Orientation")] ItemsLayoutOrientation orientation)
 		{
 			CollectionView.VerifyCollectionViewFlagEnabled(constructorHint: nameof(ItemsLayout));
 			Orientation = orientation;

Xamarin.Forms.Core/Items/ListItemsLayout.cs

@@ -3,7 +3,7 @@
 	public class ListItemsLayout : ItemsLayout
 	{
 		// TODO hartez 2018/08/29 17:28:42 Consider changing this name to LinearItemsLayout; not everything using it is a list (e.g., Carousel)	
-		public ListItemsLayout(ItemsLayoutOrientation orientation) : base(orientation)
+		public ListItemsLayout([Parameter("Orientation")] ItemsLayoutOrientation orientation) : base(orientation)
 		{
 		}