[XM] Add missing attributes on new bindings (#194)

[XM] Add missing attributes on new bindings

src/AppKit/NSAccessibility.cs

@@ -218,6 +218,7 @@ namespace XamCore.AppKit
 			return NSArray.ArrayFromHandle<NSObject> (handle);
 		}
 
+		[Introduced (PlatformName.MacOSX, 10, 9)]
 		[DllImport (Constants.AppKitLibrary)]
 		static extern bool NSAccessibilitySetMayContainProtectedContent (bool flag);
 

src/appkit.cs

@@ -21761,6 +21761,7 @@ namespace XamCore.AppKit {
 		[Field ("NSAccessibilityDocumentAttribute")]
 		NSString DocumentAttribute { get; }
 
+		[Introduced (PlatformName.MacOSX, 10, 10)]
 		[Field ("NSAccessibilityActivationPointAttribute")]
 		NSString ActivationPointAttribute { get; }
 
@@ -22515,9 +22516,11 @@ namespace XamCore.AppKit {
 
 	[Static]
 	public interface NSAccessibilityNotificationUserInfoKeys {
+		[Introduced (PlatformName.MacOSX, 10, 9)]
 		[Field ("NSAccessibilityUIElementsKey")]
 		NSString UIElementsKey { get; }
 
+		[Introduced (PlatformName.MacOSX, 10, 9)]
 		[Field ("NSAccessibilityPriorityKey")]
 		NSString PriorityKey { get; }