Add documentation and silence doxygen warning.

git-svn-id: http://root.cern.ch/svn/root/trunk@48812 27541ba8-7e3a-0410-8455-c3a389f83636

include/cling/Interpreter/DynamicLookupLifetimeHandler.h

@@ -64,6 +64,8 @@ namespace runtime {
       /// be evaluated at runtime
       /// @param[in] type The type of the object, which will help to delete
       /// it, when the LifetimeHandler goes out of scope.
+      /// @param[in] gCling The current interpreter object, which evaluate will
+      /// be called upon.
       ///
       LifetimeHandler(DynamicExprInfo* ExprInfo,
                       clang::DeclContext* DC,