Add NSImage links to documentation

Author: grynspan

Sources/Overlays/_Testing_CoreGraphics/Attachments/AttachableAsCGImage.swift

@@ -24,6 +24,8 @@ private import ImageIO
 /// be attached to a test:
 ///
 /// - [`CGImage`](https://developer.apple.com/documentation/coregraphics/cgimage)
+/// - [`NSImage`](https://developer.apple.com/documentation/appkit/nsimage)
+///   (macOS)
 ///
 /// You do not generally need to add your own conformances to this protocol. If
 /// you have an image in another format that needs to be attached to a test,

Sources/Overlays/_Testing_CoreGraphics/Attachments/Attachment+AttachableAsCGImage.swift

@@ -71,6 +71,8 @@ extension Attachment {
   /// ``AttachableAsCGImage`` protocol and can be attached to a test:
   ///
   /// - [`CGImage`](https://developer.apple.com/documentation/coregraphics/cgimage)
+  /// - [`NSImage`](https://developer.apple.com/documentation/appkit/nsimage)
+  ///   (macOS)
   @_spi(Experimental)
   @available(_uttypesAPI, *)
   public init<T>(
@@ -103,6 +105,8 @@ extension Attachment {
   /// ``AttachableAsCGImage`` protocol and can be attached to a test:
   ///
   /// - [`CGImage`](https://developer.apple.com/documentation/coregraphics/cgimage)
+  /// - [`NSImage`](https://developer.apple.com/documentation/appkit/nsimage)
+  ///   (macOS)
   @_spi(Experimental)
   public init<T>(
     _ attachableValue: T,

Sources/Overlays/_Testing_CoreGraphics/Attachments/_AttachableImageWrapper.swift

@@ -47,6 +47,8 @@ import UniformTypeIdentifiers
 /// to the ``AttachableAsCGImage`` protocol and can be attached to a test:
 ///
 /// - [`CGImage`](https://developer.apple.com/documentation/coregraphics/cgimage)
+/// - [`NSImage`](https://developer.apple.com/documentation/appkit/nsimage)
+///   (macOS)
 @_spi(Experimental)
 public struct _AttachableImageWrapper<Image>: Sendable where Image: AttachableAsCGImage {
   /// The underlying image.