`ModuleCompleter.cs` showing duplicated modules

https://github.com/santisq/PSParallelPipeline/blob/main/src/PSParallelPipeline/ModuleCompleter.cs should be filtering unique values, e.g.:

<img width="629" height="77" alt="Image" src="https://github.com/user-attachments/assets/8745daad-8099-4d29-afeb-50538dbb9f6a" />