update release notes

Author: edgarfgp

docs/release-notes/.FSharp.Compiler.Service/10.0.100.md

@@ -17,7 +17,7 @@
 * Completion: fix previous namespace considered opened [PR #18609](https://github.com/dotnet/fsharp/pull/18609)
 * Fix active pattern typechecking regression. ([Issue #18638](https://github.com/dotnet/fsharp/issues/18638), [PR #18642](https://github.com/dotnet/fsharp/pull/18642))
 * Fix nullness warnings when casting non-nullable values to `IEquatable<T>` to match C# behavior. ([Issue #18759](https://github.com/dotnet/fsharp/issues/18759))
-* Warn when a module definition is encountered inside a type definition.([Issue #10066](https://github.com/dotnet/fsharp/issues/10066), [PR #18813](https://github.com/dotnet/fsharp/pull/18813))
+* Error on invalid declarations in type definitions.([Issue #10066](https://github.com/dotnet/fsharp/issues/10066), [PR #18813](https://github.com/dotnet/fsharp/pull/18813))
 * Fix IsByRefLikeAttribute types being incorrectly suppressed in completion lists. Types like `Span<T>` and `ReadOnlySpan<T>` now appear correctly in IntelliSense.
 * Fix Show XML doc for enum fields in external metadata ([Issue #17939](https://github.com/dotnet/fsharp/issues/17939#issuecomment-3137410105), [PR #18800](https://github.com/dotnet/fsharp/pull/18800))
 

docs/release-notes/.Language/preview.md

@@ -15,6 +15,6 @@
 ### Fixed
 
 * Warn on uppercase identifiers in patterns. ([PR #15816](https://github.com/dotnet/fsharp/pull/15816))
-* Warn when a module definition is encountered inside a type definition.([Issue #10066](https://github.com/dotnet/fsharp/issues/10066), [PR #18813](https://github.com/dotnet/fsharp/pull/18813))
+* Error on invalid declarations in type definitions.([Issue #10066](https://github.com/dotnet/fsharp/issues/10066), [PR #18813](https://github.com/dotnet/fsharp/pull/18813))
 
 ### Changed

tests/fsharp/typecheck/sigs/neg17.bsl

@@ -1,6 +1,4 @@
 
-neg17.fs(70,5,70,9): parse error FS0058: Nested type definitions are not allowed. Types must be defined at module or namespace level.
-
 neg17.fs(84,17,84,33): typecheck error FS0292: The type definitions for type 'PrivateUnionType' in the signature and implementation are not compatible because the accessibility specified in the signature is more than that specified in the implementation
 
 neg17b.fs(7,17,7,31): typecheck error FS1094: The value 'privateValue' is not accessible from this code location