CPP11 — C++ keyword mapping ambiguous

Summary: The last para of section 20.1.2 says:

To avoid C++ compilation problems, every use in OMG IDL of a
C++ keyword as an identifier is mapped into the same name preceded
by the prefix "cxx". For example, an IDL interface named
"try" would be named "_cxx_try" when its name is mapped into C++.

This is ambiguous because it doesn"t make it clear what the names of types
derived from that interface shold be.

Clarify the text.