Update changelogs from fern repo (#435)

Co-authored-by: fearthecowboy <[email protected]>

Author: fern-support

fern/products/sdks/overview/csharp/changelog/2025-08-12.mdx

@@ -0,0 +1,8 @@
+## 2.1.11
+**`(fix):`** Generate explicit types everywhere, and have `dotnet format` reduce
+namespaces and namespace prefixes. 
+This creates code that is much cleaner, and can easily support
+multiple endpoints with identical names in the generated code without
+name or namespace collisions.
+
+