[appkit] Add helper properties for the NSPrintInfo PrintCore methods. Fixes #52501 (#1740)

* Add helper properties for the PrintCore methods that return the correct types instead of IntPtrs

* NSPrintInfo make bindings internal and change manual properties to getter methods

https://bugzilla.xamarin.com/show_bug.cgi?id=52501

src/AppKit/NSPrintInfo.cs

@@ -0,0 +1,24 @@
+using System;
+using XamCore.PrintCore;
+
+namespace XamCore.AppKit {
+	public partial class NSPrintInfo {
+		public PMPrintSession GetPrintSession ()
+		{
+			var ptr = GetPMPrintSession ();
+			return new PMPrintSession (ptr, false);
+		}
+
+		public PMPageFormat GetPageFormat ()
+		{
+			var ptr = GetPMPageFormat ();
+			return new PMPageFormat (ptr, false);
+		}
+
+		public PMPrintSettings GetPrintSettings ()
+		{
+			var ptr = GetPMPrintSettings ();
+			return new PMPrintSettings (ptr, false);
+		}
+	}
+}

src/appkit.cs

@@ -11808,12 +11808,21 @@ namespace XamCore.AppKit {
 		[Export ("printSettings")]
 		NSMutableDictionary PrintSettings { get; }
 
+#if XAMCORE_4_0
+		[Internal]
+#endif
 		[Export ("PMPrintSession")]
 		IntPtr GetPMPrintSession ();
 
+#if XAMCORE_4_0
+		[Internal]
+#endif
 		[Export ("PMPageFormat")]
 		IntPtr GetPMPageFormat ();
 
+#if XAMCORE_4_0
+		[Internal]
+#endif
 		[Export ("PMPrintSettings")]
 		IntPtr GetPMPrintSettings ();
 

src/frameworks.sources

@@ -118,6 +118,7 @@ APPKIT_SOURCES = \
 	AppKit/NSPopUpButton.cs \
 	AppKit/NSPopUpButtonCell.cs \
 	AppKit/NSPredicateEditorRowTemplate.cs \
+	AppKit/NSPrintInfo.cs \
 	AppKit/NSPrintPanel.cs \
 	AppKit/NSResponder.cs \
 	AppKit/NSScreen.cs \