clarification note for 18.1

[Rafkind, Jon]

It would be helpful if section 18.1 of JSR 335 to give examples for each of the meta variables. Specifically, I was confused about what 'S' was. I finally figured out it is either a proper type or a type variable that can contain inference variables.

Where 'a' is an inference variable (alpha), S can be
  Integer
  List<Integer>
  List<a>

But not
  a

And I assume this is not even possible
  a<a>