[AppKit] Mark deprecated API as deprecated, not obsolete. (#14234)

These APIs are marked as deprecated in the headers (i.e. they still exist), so
mark them as such.

src/appkit.cs

@@ -1396,7 +1396,7 @@ namespace AppKit {
 		[Export ("appendBezierPathWithArcFromPoint:toPoint:radius:")]
 		void AppendPathWithArc (CGPoint point1, CGPoint point2, nfloat radius);
 
-		[Obsoleted (PlatformName.MacOSX, 10, 13, message: "Use 'AppendPathWithCGGlyph (CGGlyph, NSFont)' instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 13, message: "Use 'AppendPathWithCGGlyph (CGGlyph, NSFont)' instead.")]
 		[Export ("appendBezierPathWithGlyph:inFont:")]
 		void AppendPathWithGlyph (uint /* NSGlyph = unsigned int */ glyph, NSFont font);
 
@@ -1404,7 +1404,7 @@ namespace AppKit {
 		void _AppendPathWithGlyphs (IntPtr glyphs, nint count, NSFont font);
 
 		//IntPtr is exposed because the packedGlyphs should be treated as a "black box"
-		[Obsoleted (PlatformName.MacOSX, 10, 13, message: "Use 'Append (uint[], NSFont)' instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 13, message: "Use 'Append (uint[], NSFont)' instead.")]
 		[Export ("appendBezierPathWithPackedGlyphs:")]
 		void AppendPathWithPackedGlyphs (IntPtr packedGlyphs);
 
@@ -26374,43 +26374,43 @@ namespace AppKit {
 
 	[NoMacCatalyst]
 	interface NSObjectAccessibilityExtensions {
-		[Obsoleted (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
 		[Export ("accessibilityAttributeNames")]
 		NSArray AccessibilityAttributeNames { get; }
 
-		[Obsoleted (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
 		[Export ("accessibilityAttributeValue:")]
 		NSObject GetAccessibilityValue (NSString attribute);
 
-		[Obsoleted (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
 		[Export ("accessibilityIsAttributeSettable:")]
 		bool IsAccessibilityAttributeSettable (NSString attribute);
 
-		[Obsoleted (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
 		[Export ("accessibilitySetValue:forAttribute:")]
 		void SetAccessibilityValue (NSString attribute, NSObject value);
 
-		[Obsoleted (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
 		[Export ("accessibilityParameterizedAttributeNames")]
 		NSArray AccessibilityParameterizedAttributeNames { get; }
 
-		[Obsoleted (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
 		[Export ("accessibilityAttributeValue:forParameter:")]
 		NSObject GetAccessibilityValue (NSString attribute, NSObject parameter);
 
-		[Obsoleted (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
 		[Export ("accessibilityActionNames")]
 		NSArray AccessibilityActionNames { get; }
 
-		[Obsoleted (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
 		[Export ("accessibilityActionDescription:")]
 		NSString GetAccessibilityActionDescription (NSString action);
 
-		[Obsoleted (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
 		[Export ("accessibilityPerformAction:")]
 		void AccessibilityPerformAction (NSString action);
 
-		[Obsoleted (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
+		[Deprecated (PlatformName.MacOSX, 10, 10, message: "Use the NSAccessibility protocol methods instead.")]
 		[Export ("accessibilityIsIgnored")]
 		bool AccessibilityIsIgnored { get; }