[m-rev.] for review: insts in mode error messages

[Zoltan Somogyi]

On Mon, 30 Nov 2015 02:24:47 +1100 (AEDT), "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> Does anyone see any future use for mercury_output_expanded_inst
> or mercury_expanded_inst_to_string? With my recent change to
> mode_errors.m and the current one to add_mutable_aux_preds.m,
> I have deleted both uses of these predicates, and I think that any
> future code that wants to print error messages involving insts
> should use the code in error_msg_inst.m, not these predicates.
> I therefore think they should be deleted, along with the typeclass
> that they made necessary. Does anyone object?

Since noone objected, I am deleting this dead code.

Zoltan.