[m-rev.] for post-commit review: print more info for foreign types

[Julien Fischer]

Hi Zoltan,

On Sun, 31 May 2015, Zoltan Somogyi wrote:

> The code change is simple. I am more after opinions on exactly how
> the extra info is presented to the user.

Presenting it as you have done,

     <<foreign(coord, 0xXXXX)>>

is fine.  I think the type name should be module qualified and you
probably also want to include its arity, since things like the following
are possible:

     :- type foo.
     :- type foo(T).
     :- type foo(T, U).

     :- pragma foreign_type("C", foo, "void *").
     :- pragma foreign_type("C", foo(T), "void *").
     :- pragma foreign_type("C", foo(T, U), "void *").

Cheers,
Julien.