Rename "..Ex" to "..Helper"

PixiEditor/Helpers/Extensions/Int32RectEx.cs → PixiEditor/Helpers/Extensions/Int32RectHelper.cs

@@ -4,7 +4,7 @@ using System.Windows;
 
 namespace PixiEditor.Helpers.Extensions
 {
-    public static class Int32RectEx
+    public static class Int32RectHelper
     {
         public static Int32Rect Intersect(this Int32Rect rect, Int32Rect other)
         {

PixiEditor/Helpers/Extensions/SKRectIEx.cs → PixiEditor/Helpers/Extensions/SKRectIHelper.cs

@@ -3,7 +3,7 @@ using System.Windows;
 
 namespace PixiEditor.Helpers.Extensions
 {
-    public static class SKRectIEx
+    public static class SKRectIHelper
     {
         public static Int32Rect ToInt32Rect(this SKRectI rect)
         {