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.

まず、同じモジュール内の関数間で WhatIfPreference を渡した場合の SupportsShouldProcess の動作を再現し、次に SupportsShouldProcess ルールとモジュール境界の扱いを調査します。同じモジュール内の関数での WhatIf または WhatIfPreference の明示的な使用が、誤検出なしに一貫して認識されれば完了です。