[Doxygen] Internet module fixes

src/internet/helper/internet-stack-helper.h

@@ -297,8 +297,6 @@ private:
    */
   static void CreateAndAggregateObjectFromTypeId (Ptr<Node> node, const std::string typeId);
 
-  static void Cleanup (void);
-
   /**
    * \brief checks if there is an hook to a Pcap wrapper
    * \param ipv4 pointer to the IPv4 object

src/internet/model/rtt-estimator.cc

@@ -38,6 +38,7 @@ NS_LOG_COMPONENT_DEFINE ("RttEstimator");
 
 NS_OBJECT_ENSURE_REGISTERED (RttEstimator);
 
+/// Tolerance used to check reciprocal of two numbers.
 static const double TOLERANCE = 1e-6;
 
 TypeId