Make F.16 consistent, closes #2324

Author: hsutter

CppCoreGuidelines.md

@@ -3037,10 +3037,11 @@ If you need the notion of an optional value, use a pointer, `std::optional`, or
 
 ##### Enforcement
 
-* (Simple) ((Foundation)) Warn when a parameter being passed by value has a size greater than `2 * sizeof(void*)`.
+* (Simple) ((Foundation)) Warn when a parameter being passed by value has a size greater than `4 * sizeof(void*)`.
   Suggest using a reference to `const` instead.
 * (Simple) ((Foundation)) Warn when a parameter passed by reference to `const` has a size less or equal than `2 * sizeof(void*)`. Suggest passing by value instead.
 * (Simple) ((Foundation)) Warn when a parameter passed by reference to `const` is `move`d.
+* (Not simple) Note: A stricter enforcement would depend on the performance characteristics of the target architecture.
 
 ##### Exception