aux vars: update C++ comment to reflect last changes

preprocessor/DynamicModel.cc

@@ -4017,7 +4017,7 @@ DynamicModel::substituteLeadLagInternal(aux_var_t type, bool deterministic_model
 
   // Order of auxiliary variable definition equations:
   //  - expectation (entered before this function is called)
-  //  - lead variables from lower lead to higher lead (need to be listed in reverse order)
+  //  - lead variables from lower lead to higher lead
   //  - lag variables from lower lag to higher lag
   copy(neweqs.begin(), neweqs.end(), back_inserter(aux_equations));