PD: modernize C++: use default member init

src/Mod/PartDesign/App/FeatureAddSub.cpp

@@ -43,7 +43,6 @@ namespace PartDesign {
 PROPERTY_SOURCE(PartDesign::FeatureAddSub, PartDesign::Feature)
 
 FeatureAddSub::FeatureAddSub()
-  :  addSubType(Additive)
 {
     ADD_PROPERTY(AddSubShape,(TopoDS_Shape()));
     ADD_PROPERTY_TYPE(Refine,(0),"Part Design",(App::PropertyType)(App::Prop_None),"Refine shape (clean up redundant edges) after adding/subtracting");

src/Mod/PartDesign/App/FeatureAddSub.h

@@ -52,7 +52,7 @@ public:
     App::PropertyBool Refine;
 
 protected:
-    Type addSubType;
+    Type addSubType{Additive};
 
     TopoDS_Shape refineShapeIfActive(const TopoDS_Shape&) const;
 };

src/Mod/PartDesign/App/FeaturePrimitive.cpp

@@ -61,7 +61,6 @@ const App::PropertyQuantityConstraint::Constraints quantityRangeZero = { 0.0, FL
 PROPERTY_SOURCE_WITH_EXTENSIONS(PartDesign::FeaturePrimitive, PartDesign::FeatureAddSub)
 
 FeaturePrimitive::FeaturePrimitive()
-  :  primitiveType(Box)
 {
     Part::AttachExtension::initExtension(this);
 }