Adjusted class visibility

Source/QuestPDF/Drawing/SkiaPictureCanvas.cs

@@ -7,7 +7,7 @@ using SkiaSharp;
 
 namespace QuestPDF.Drawing
 {
-    public class PreviewerPicture
+    internal class PreviewerPicture
     {
         public SKPicture Picture { get; set; }
         public Size Size { get; set; }

Source/QuestPDF/Drawing/SpacePlanType.cs

@@ -1,6 +1,6 @@
 namespace QuestPDF.Drawing
 {
-    public enum SpacePlanType
+    internal enum SpacePlanType
     {
         Wrap,
         PartialRender,