release notes

Author: majocha

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

@@ -7,6 +7,7 @@
 * Fix: warn FS0049 on upper union case label. ([PR #19003](https://github.com/dotnet/fsharp/pull/19003))
 * Type relations cache: handle potentially "infinite" types ([PR #19010](https://github.com/dotnet/fsharp/pull/19010))  
 * Disallow recursive structs with lifted type parameters ([Issue #18993](https://github.com/dotnet/fsharp/issues/18993), [PR #19031](https://github.com/dotnet/fsharp/pull/19031))
+* Type relations cache: handle unsolved type variables ([Issue #19037](https://github.com/dotnet/fsharp/issues/19037)) ([PR #19040](https://github.com/dotnet/fsharp/pull/19040))
 
 ### Added