Promote Windows image attachments to API.

Remove `@_spi` and adjust documentation as needed. Pending approval of
[ST-0015](https://forums.swift.org/t/st-0015-image-attachments-in-swift-testing-windows/82241).

Author: grynspan

Sources/Overlays/_Testing_CoreGraphics/Attachments/AttachableAsCGImage.swift

@@ -27,9 +27,7 @@ private import ImageIO
 /// |-|-|
 /// | macOS | [`CGImage`](https://developer.apple.com/documentation/coregraphics/cgimage), [`CIImage`](https://developer.apple.com/documentation/coreimage/ciimage), [`NSImage`](https://developer.apple.com/documentation/appkit/nsimage) |
 /// | iOS, watchOS, tvOS, and visionOS | [`CGImage`](https://developer.apple.com/documentation/coregraphics/cgimage), [`CIImage`](https://developer.apple.com/documentation/coreimage/ciimage), [`UIImage`](https://developer.apple.com/documentation/uikit/uiimage) |
-/// @Comment {
 /// | Windows | [`HBITMAP`](https://learn.microsoft.com/en-us/windows/win32/gdi/bitmaps), [`HICON`](https://learn.microsoft.com/en-us/windows/win32/menurc/icons), [`IWICBitmapSource`](https://learn.microsoft.com/en-us/windows/win32/api/wincodec/nn-wincodec-iwicbitmapsource) (including its subclasses declared by Windows Imaging Component) |
-/// }
 ///
 /// 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_WinSDK/Attachments/AttachableAsIWICBitmapSource.swift

@@ -32,7 +32,6 @@ public import WinSDK
 /// 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,
 /// first convert it to an instance of one of the types above.
-@_spi(Experimental)
 public protocol _AttachableByAddressAsIWICBitmapSource {
   /// Create a WIC bitmap source representing an instance of this type at the
   /// given address.
@@ -112,14 +111,21 @@ public protocol _AttachableByAddressAsIWICBitmapSource {
 /// 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,
 /// first convert it to an instance of one of the types above.
-@_spi(Experimental)
+///
+/// @Metadata {
+///   @Available(Swift, introduced: 6.3)
+/// }
 public protocol AttachableAsIWICBitmapSource: _AttachableAsImage, SendableMetatype {
   /// Create a WIC bitmap source representing an instance of this type.
   ///
   /// - Returns: A pointer to a new WIC bitmap source representing this image.
   ///   The caller is responsible for releasing this image when done with it.
   ///
   /// - Throws: Any error that prevented the creation of the WIC bitmap source.
+  ///
+  /// @Metadata {
+  ///   @Available(Swift, introduced: 6.3)
+  /// }
   func copyAttachableIWICBitmapSource() throws -> UnsafeMutablePointer<IWICBitmapSource>
 
   /// Create a WIC bitmap representing an instance of this type.

Sources/Overlays/_Testing_WinSDK/Attachments/AttachableImageFormat+CLSID.swift

@@ -9,10 +9,9 @@
 //
 
 #if os(Windows)
-@_spi(Experimental) public import Testing
+public import Testing
 public import WinSDK
 
-@_spi(Experimental)
 extension AttachableImageFormat {
   private static let _encoderPathExtensionsByCLSID = Result<[UInt128: [String]], any Error> {
     var result = [UInt128: [String]]()
@@ -235,6 +234,10 @@ extension AttachableImageFormat {
   ///
   /// For example, if this image format equals ``png``, the value of this
   /// property equals [`CLSID_WICPngEncoder`](https://learn.microsoft.com/en-us/windows/win32/wic/-wic-guids-clsids#wic-guids-and-clsids).
+  ///
+  /// @Metadata {
+  ///   @Available(Swift, introduced: 6.3)
+  /// }
   public var encoderCLSID: CLSID {
     switch kind {
     case .png:
@@ -263,6 +266,10 @@ extension AttachableImageFormat {
   /// result is undefined. For a list of image encoder classes supported by WIC,
   /// see the documentation for the [`IWICBitmapEncoder`](https://learn.microsoft.com/en-us/windows/win32/api/wincodec/nn-wincodec-iwicbitmapencoder)
   /// class.
+  ///
+  /// @Metadata {
+  ///   @Available(Swift, introduced: 6.3)
+  /// }
   public init(encoderCLSID: CLSID, encodingQuality: Float = 1.0) {
     if encoderCLSID == CLSID_WICPngEncoder {
       self = .png

Sources/Overlays/_Testing_WinSDK/Attachments/HBITMAP+AttachableAsIWICBitmapSource.swift

@@ -12,7 +12,6 @@
 private import Testing
 public import WinSDK
 
-@_spi(Experimental)
 extension HBITMAP__: _AttachableByAddressAsIWICBitmapSource {
   public static func _copyAttachableIWICBitmapSource(
     from imageAddress: UnsafeMutablePointer<Self>,

Sources/Overlays/_Testing_WinSDK/Attachments/HICON+AttachableAsIWICBitmapSource.swift

@@ -12,7 +12,6 @@
 private import Testing
 public import WinSDK
 
-@_spi(Experimental)
 extension HICON__: _AttachableByAddressAsIWICBitmapSource {
   public static func _copyAttachableIWICBitmapSource(
     from imageAddress: UnsafeMutablePointer<Self>,

Sources/Overlays/_Testing_WinSDK/Attachments/IWICBitmapSource+AttachableAsIWICBitmapSource.swift

@@ -34,31 +34,14 @@ public import WinSDK
 /// allows us to reuse code across all subclasses of `IWICBitmapSource`.
 protocol IWICBitmapSourceProtocol: _AttachableByAddressAsIWICBitmapSource {}
 
-@_spi(Experimental)
 extension IWICBitmapSource: _AttachableByAddressAsIWICBitmapSource, IWICBitmapSourceProtocol {}
-
-@_spi(Experimental)
 extension IWICBitmap: _AttachableByAddressAsIWICBitmapSource, IWICBitmapSourceProtocol {}
-
-@_spi(Experimental)
 extension IWICBitmapClipper: _AttachableByAddressAsIWICBitmapSource, IWICBitmapSourceProtocol {}
-
-@_spi(Experimental)
 extension IWICBitmapFlipRotator: _AttachableByAddressAsIWICBitmapSource, IWICBitmapSourceProtocol {}
-
-@_spi(Experimental)
 extension IWICBitmapFrameDecode: _AttachableByAddressAsIWICBitmapSource, IWICBitmapSourceProtocol {}
-
-@_spi(Experimental)
 extension IWICBitmapScaler: _AttachableByAddressAsIWICBitmapSource, IWICBitmapSourceProtocol {}
-
-@_spi(Experimental)
 extension IWICColorTransform: _AttachableByAddressAsIWICBitmapSource, IWICBitmapSourceProtocol {}
-
-@_spi(Experimental)
 extension IWICFormatConverter: _AttachableByAddressAsIWICBitmapSource, IWICBitmapSourceProtocol {}
-
-@_spi(Experimental)
 extension IWICPlanarFormatConverter: _AttachableByAddressAsIWICBitmapSource, IWICBitmapSourceProtocol {}
 
 // MARK: - Upcasting conveniences
@@ -96,7 +79,6 @@ extension UnsafeMutablePointer where Pointee: IWICBitmapSourceProtocol {
 
 // MARK: - _AttachableByAddressAsIWICBitmapSource implementation
 
-@_spi(Experimental)
 extension IWICBitmapSourceProtocol {
   public static func _copyAttachableIWICBitmapSource(
     from imageAddress: UnsafeMutablePointer<Self>,
@@ -120,7 +102,6 @@ extension IWICBitmapSourceProtocol {
 }
 
 extension IWICBitmapSource {
-  @_spi(Experimental)
   public static func _copyAttachableIWICBitmapSource(
     from imageAddress: UnsafeMutablePointer<Self>,
     using factory: UnsafeMutablePointer<IWICImagingFactory>

Sources/Overlays/_Testing_WinSDK/Attachments/UnsafeMutablePointer+AttachableAsIWICBitmapSource.swift

@@ -12,8 +12,13 @@
 private import Testing
 public import WinSDK
 
-@_spi(Experimental)
+/// @Metadata {
+///   @Available(Swift, introduced: 6.3)
+/// }
 extension UnsafeMutablePointer: _AttachableAsImage, AttachableAsIWICBitmapSource where Pointee: _AttachableByAddressAsIWICBitmapSource {
+  /// @Metadata {
+  ///   @Available(Swift, introduced: 6.3)
+  /// }
   public func copyAttachableIWICBitmapSource() throws -> UnsafeMutablePointer<IWICBitmapSource> {
     let factory = try IWICImagingFactory.create()
     defer {

Sources/Overlays/_Testing_WinSDK/Attachments/_AttachableImageWrapper+AttachableWrapper.swift

@@ -9,10 +9,9 @@
 //
 
 #if os(Windows)
-@_spi(Experimental) public import Testing
+public import Testing
 private import WinSDK
 
-@_spi(Experimental)
 extension _AttachableImageWrapper: Attachable, AttachableWrapper where Image: AttachableAsIWICBitmapSource {
   public func withUnsafeBytes<R>(for attachment: borrowing Attachment<_AttachableImageWrapper>, _ body: (UnsafeRawBufferPointer) throws -> R) throws -> R {
     // Create an in-memory stream to write the image data to. Note that Windows

Sources/Overlays/_Testing_WinSDK/ReexportTesting.swift

@@ -8,4 +8,4 @@
 // See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 //
 
-@_exported @_spi(Experimental) @_spi(ForToolsIntegrationOnly) public import Testing
+@_exported public import Testing

Sources/Testing/Attachments/Images/AttachableImageFormat.swift

@@ -23,10 +23,8 @@
 /// - On Apple platforms, you can use [`CGImageDestinationCopyTypeIdentifiers()`](https://developer.apple.com/documentation/imageio/cgimagedestinationcopytypeidentifiers())
 ///   from the [Image I/O framework](https://developer.apple.com/documentation/imageio)
 ///   to determine which formats are supported.
-/// @Comment {
 /// - On Windows, you can use [`IWICImagingFactory.CreateComponentEnumerator()`](https://learn.microsoft.com/en-us/windows/win32/api/wincodec/nf-wincodec-iwicimagingfactory-createcomponentenumerator)
 ///   to enumerate the available image encoders.
-/// }
 ///
 /// @Metadata {
 ///   @Available(Swift, introduced: 6.3)