Update noteworthy-differences.rst

Added section (inspired by @carnaval) about C++ static dispatch vs. dynamic dispatch.

doc/manual/noteworthy-differences.rst

@@ -344,4 +344,7 @@ Noteworthy differences from C/C++
  For example: ``@enum(Fruit, Banana=1, Apple, Pear)``
 - By convention, functions that modify their arguments have a ``!`` at the end of the name,
  for example ``push!``.
-
+- In C++, by default, you have static dispatch, i.e. you need to annotate a function as virtual,
+ in order to have dynamic dispatch.
+ On the other hand, in Julia every method is "virtual" (although it's more general than that
+ since methods are dispatched on every argument type, not only ``this``, using the most-specific-declaration rule).