[exercise fluidsystem][2pproblem] cleanup

exercises/exercise-fluidsystem/2pproblem.hh

@@ -160,6 +160,8 @@ public:
 
         // set the depth of the bottom of the reservoir
         depthBOR_ = this->fvGridGeometry().bBoxMax()[dimWorld-1];
+
+        // plot density over pressure of the phase consisting of your component
         if(getParam<bool>("Output.PlotDensity"))
             plotDensity_();
     }