SupportsShouldProcess doesn't care for WhatIfPreference

Summary of the new feature
It seems the SupportShouldProcess rule doesn't always pick up WhatIf being passed to a function later on. It mostly does this for external modules (that do it properly), but not when the functions are within the same module (different files) that I am actually building.

Proposed technical implementation details (optional)
I guess a prescan should be made and if there are commands with explicit WhatIf calls or WhatIfPreference calls it should treat it as condition to ignore.

首先重現 SupportsShouldProcess 的行為，測試在同一模組中的函式之間傳遞 WhatIfPreference，然後檢查 SupportsShouldProcess 規則及其對模組邊界的處理。完成標準是：同一模組中的函式明確使用 WhatIf 或 WhatIfPreference 時能夠一致地被識別，且不會產生誤報。