Move release notes to correct file (.Language/preview.md)

Moved the --disableLanguageFeature feature entry from .FSharp.Compiler.Service/11.0.0.md to .Language/preview.md as it's a language feature, not a compiler service API change. Used placeholder PR number "TBD" since gh CLI requires GH_TOKEN environment variable which is not available.

Addresses comment 2630841469 from @T-Gro.

Co-authored-by: T-Gro <46543583+T-Gro@users.noreply.github.com>

Author: Copilot

docs/release-notes/.FSharp.Compiler.Service/11.0.0.md

@@ -20,7 +20,6 @@
 * Add FSharpCodeCompletionOptions ([PR #19030](https://github.com/dotnet/fsharp/pull/19030))
 * Type checker: recover on checking binding parameter constraints ([#19046](https://github.com/dotnet/fsharp/pull/19046))
 * Debugger: provide breakpoint ranges for short lambdas ([#19067](https://github.com/dotnet/fsharp/pull/19067))
-* Add `--disableLanguageFeature` command line switch to selectively disable specific F# language features ([PR #NNNNN](https://github.com/dotnet/fsharp/pull/NNNNN))
 
 ### Changed
 

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

@@ -11,6 +11,7 @@
 * Allow `let!`, `use!`, `and!` type annotations without requiring parentheses (([PR #18508](https://github.com/dotnet/fsharp/pull/18508) and [PR #18682](https://github.com/dotnet/fsharp/pull/18682)))
 * Exception names are now validated for illegal characters using the same mechanism as types/modules/namespaces ([Issue #18763](https://github.com/dotnet/fsharp/issues/18763))
 * Support tail calls in computation expressions ([PR #18804](https://github.com/dotnet/fsharp/pull/18804))
+* Add `--disableLanguageFeature` CLI switch and MSBuild property to selectively disable specific F# language features on a per-project basis. ([PR #TBD](https://github.com/dotnet/fsharp/pull/TBD))
 
 ### Fixed