CPP13 — IDL that is not IDL!

Summary: The C++ language mapping chapter contains many blocks of IDL like stuff
with the comment

// IDL

in the first line, but the stuff in the block is not valid IDL for
various reasons:

Uses "pseudo" as an apparent keyword.

(ii) Contains declarations like

attribute exception exception;

I suggest that the comment "// IDL" be replaced by "// Augmented IDL
(see "Usage" on page x-y)" cross-referencing to section 20.23 Usage, so
that people know for sure that this is not IDL.

Furthermore, to make the claim in section 20.23 true, the declaration:

attribute exception exception;

should be fixed to be something else, or alternatively, the exceptional
use of exception should be called out as a specific augmentation of IDL
in section 20.23.