[framework] remove reference to closed issue. (#128007)

Shaders are supported everywhere but HTML backend. We missed this doc update.

packages/flutter/lib/src/material/ink_sparkle.dart

@@ -14,11 +14,8 @@ import 'material.dart';
 /// Begin a Material 3 ink sparkle ripple, centered at the tap or click position
 /// relative to the [referenceBox].
 ///
-/// This effect relies on a shader, and therefore hardware acceleration.
-/// Currently, this is only supported by certain C++ engine platforms. The
-/// platforms that are currently supported are Android, iOS, MacOS, Windows,
-/// and Linux. Support for CanvasKit web can be tracked here:
-///  - https://github.com/flutter/flutter/issues/85238
+/// This effect relies on a shader and therefore is unsupported on the Flutter
+/// Web HTML backend.
 ///
 /// To use this effect, pass an instance of [splashFactory] to the
 /// `splashFactory` parameter of either the Material [ThemeData] or any