ReParticle: privatize

Resample/Particle/ReParticle.h

@@ -61,10 +61,9 @@ public:
 
     virtual complex_t formfactor_at_bottom(C3 q) const;
 
-protected:
+private:
     std::unique_ptr<const IFormFactor> m_ff;
 
-    // private:
     ReParticle(const std::optional<size_t>& i_layer, IFormFactor* ff, const Material* material,
                const Material* ambient_material, const R3* position, const RotMatrix* rotMatrix);