[TD]fix 2 tidy warnings

src/Mod/TechDraw/Gui/QGIEdge.cpp

@@ -122,6 +122,7 @@ QPainterPath QGIEdge::shape() const
 
 void QGIEdge::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
 {
+    Q_UNUSED(event)
     QGIView *parent = dynamic_cast<QGIView *>(parentItem());
     if (parent && parent->getViewObject() && parent->getViewObject()->isDerivedFrom(TechDraw::DrawViewPart::getClassTypeId())) {
         TechDraw::DrawViewPart *baseFeat = static_cast<TechDraw::DrawViewPart *>(parent->getViewObject());

src/Mod/TechDraw/Gui/TaskLineDecor.cpp

@@ -133,6 +133,7 @@ TechDraw::LineFormat *TaskLineDecor::getFormatAccessPtr(const std::string &edgeN
             }
         }
     }
+    return nullptr;
 }
 
 void TaskLineDecor::initializeRejectArrays()