[AppKit] Make NSTextView implement the NSColorChanging protocol in .NET. (#14071)

Also change the NSColorChanging.ChangeColor method to not be deprecated
anymore, Apple's headers say nothing of the sort.

src/appkit.cs

@@ -4377,7 +4377,6 @@ namespace AppKit {
 	{
 		[Abstract]
 		[Export ("changeColor:")]
-		[Deprecated (PlatformName.MacOSX, 11, 0, message: "Use 'NSColorChanging' instead.")]
 		void ChangeColor ([NullAllowed] NSColorPanel sender);
 	}
 
@@ -18975,8 +18974,8 @@ namespace AppKit {
 	[NoMacCatalyst]
 	[BaseType (typeof (NSText), Delegates=new string [] { "Delegate" }, Events=new Type [] { typeof (NSTextViewDelegate)})]
 	partial interface NSTextView : NSTextInputClient, NSTextLayoutOrientationProvider, NSDraggingSource, NSTextFinderClient, NSAccessibilityNavigableStaticText, NSCandidateListTouchBarItemDelegate, NSTouchBarDelegate, NSMenuItemValidation, NSUserInterfaceValidations, NSTextInput, NSTextContent
-#if XAMCORE_4_0
-		, NSColorChanging, // ChangeColor has the wrong param type
+#if NET
+		, NSColorChanging // ChangeColor has the wrong param type
 #endif
 	{
 		[DesignatedInitializer]
@@ -19060,8 +19059,10 @@ namespace AppKit {
 		[Export ("alignJustified:")]
 		void AlignJustified (NSObject sender);
 
+#if !NET
 		[Export ("changeColor:")]
 		void ChangeColor (NSObject sender);
+#endif
 
 		[Export ("changeAttributes:")]
 		void ChangeAttributes (NSObject sender);

tests/xtro-sharpie/api-annotations-dotnet/macOS-AppKit.ignore

@@ -214,9 +214,6 @@
 ## NSGlyphStorage protocol not bound
 !missing-protocol-conformance! NSLayoutManager should conform to NSGlyphStorage (defined in 'NSGlyphGeneration' category)
 
-## Fixed in XAMCORE_4_0
-!missing-protocol-conformance! NSTextView should conform to NSColorChanging
-
 ## NSStandardKeyBindingResponding is strange case - technically on NSResponder but responder subclasses can implement any that make sense.
 !missing-protocol-conformance! NSTextView should conform to NSStandardKeyBindingResponding
 !missing-protocol-conformance! NSResponder should conform to NSStandardKeyBindingResponding (defined in 'NSStandardKeyBindingMethods' category)
@@ -1037,7 +1034,6 @@
 !missing-null-allowed! 'System.Void AppKit.NSTextFinderBarContainer::set_FindBarView(AppKit.NSView)' is missing an [NullAllowed] on parameter #0
 !missing-null-allowed! 'System.Void AppKit.NSTextView::AlignJustified(Foundation.NSObject)' is missing an [NullAllowed] on parameter #0
 !missing-null-allowed! 'System.Void AppKit.NSTextView::ChangeAttributes(Foundation.NSObject)' is missing an [NullAllowed] on parameter #0
-!missing-null-allowed! 'System.Void AppKit.NSTextView::ChangeColor(Foundation.NSObject)' is missing an [NullAllowed] on parameter #0
 !missing-null-allowed! 'System.Void AppKit.NSTextView::ChangeDocumentBackgroundColor(Foundation.NSObject)' is missing an [NullAllowed] on parameter #0
 !missing-null-allowed! 'System.Void AppKit.NSTextView::ChangeLayoutOrientation(Foundation.NSObject)' is missing an [NullAllowed] on parameter #0
 !missing-null-allowed! 'System.Void AppKit.NSTextView::CheckTextInDocument(Foundation.NSObject)' is missing an [NullAllowed] on parameter #0