Ratsnest: Force update after modifying visible nets

After adjusting the ratsnest, we force the view update to re-draw the
ratsnest to the screen.  This is not required for Linux but seems to
have no ill effects and may help MSW show local ratsnest changes.

Possibly related to lp:1800301

pcbnew/tools/pcb_editor_control.cpp

@@ -1104,7 +1104,9 @@ static bool showLocalRatsnest( TOOL_MANAGER* aToolMgr, BOARD* aBoard, const VECT
         }
     }
 
-    aToolMgr->GetView()->MarkTargetDirty( KIGFX::TARGET_NONCACHED );
+    auto frame = static_cast<PCB_BASE_FRAME*>(aToolMgr->GetEditFrame());
+    static_cast<PCB_DRAW_PANEL_GAL*>( frame->GetGalCanvas() )->RedrawRatsnest();
+
     return true;
 }