Minor SAL fix (#495)

ScreenGrab/ScreenGrab11.h

@@ -41,6 +41,6 @@ namespace DirectX
         _In_ REFGUID guidContainerFormat,
         _In_z_ const wchar_t* fileName,
         _In_opt_ const GUID* targetFormat = nullptr,
-        _In_opt_ std::function<void __cdecl(IPropertyBag2*)> setCustomProps = nullptr,
+        _In_ std::function<void __cdecl(IPropertyBag2*)> setCustomProps = nullptr,
         _In_ bool forceSRGB = false);
 }

ScreenGrab/ScreenGrab12.h

@@ -63,7 +63,7 @@ namespace DirectX
         D3D12_RESOURCE_STATES beforeState = D3D12_RESOURCE_STATE_RENDER_TARGET,
         D3D12_RESOURCE_STATES afterState = D3D12_RESOURCE_STATE_RENDER_TARGET,
         _In_opt_ const GUID* targetFormat = nullptr,
-        _In_opt_ std::function<void __cdecl(IPropertyBag2*)> setCustomProps = nullptr,
+        _In_ std::function<void __cdecl(IPropertyBag2*)> setCustomProps = nullptr,
         bool forceSRGB = false);
 #endif
 }

ScreenGrab/ScreenGrab9.h

@@ -43,5 +43,5 @@ namespace DirectX
         _In_ REFGUID guidContainerFormat,
         _In_z_ const wchar_t* fileName,
         _In_opt_ const GUID* targetFormat = nullptr,
-        _In_opt_ std::function<void __cdecl(IPropertyBag2*)> setCustomProps = nullptr);
+        _In_ std::function<void __cdecl(IPropertyBag2*)> setCustomProps = nullptr);
 }