avoid confusion: this is merely about "isabelle dotnet_setup", no codegen yet;

--- a/ANNOUNCE	Thu Aug 10 20:42:18 2023 +0200
+++ b/ANNOUNCE	Sun Aug 13 15:06:17 2023 +0200
@@ -28,7 +28,6 @@
 
 * System: "isabelle profiling" tool produces ML heap statistics.
 
-* Support for the Dotnet platform (.NET) and Fsharp (F#).
 
 
 You may get Isabelle2023 from the following mirror sites: