C#: Add change note

Author: hvitved

csharp/ql/lib/change-notes/2023-11-09-mad-generics.md

@@ -0,0 +1,24 @@
+---
+category: minorAnalysis
+---
+
+* The models-as-data format for types and methods with type parameters has been changed to include the names of the type parameters. For example, instead of writing
+```yml
+extensions:
+  - addsTo:
+      pack: codeql/csharp-all
+      extensible: summaryModel
+      data:
+        - ["System.Collections.Generic", "IList<>", True, "Insert", "(System.Int32,T)", "", "Argument[1]", "Argument[this].Element", "value", "manual"]
+        - ["System.Linq", "Enumerable", False, "Select<,>", "(System.Collections.Generic.IEnumerable<TSource>,System.Func<TSource,System.Int32,TResult>)", "", "Argument[0].Element", "Argument[1].Parameter[0]", "value", "manual"]
+```
+one now writes
+```yml
+extensions:
+  - addsTo:
+      pack: codeql/csharp-all
+      extensible: summaryModel
+      data:
+        - ["System.Collections.Generic", "IList<T>", True, "Insert", "(System.Int32,T)", "", "Argument[1]", "Argument[this].Element", "value", "manual"]
+        - ["System.Linq", "Enumerable", False, "Select<TSource,TResult>", "(System.Collections.Generic.IEnumerable<TSource>,System.Func<TSource,System.Int32,TResult>)", "", "Argument[0].Element", "Argument[1].Parameter[0]", "value", "manual"]
+```