[m-rev.] for post-commit review: fix diagnostic about type ambiguity

[Peter Wang]

On Mon, 27 May 2024 19:29:32 +1000 "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> Handle errors about ambiguous types better.
> 
> compiler/typecheck_error_overload.m:
>     Generalize the error message about variables having ambiguous types.
>     Instead of printing just two possibilities regardless of how many exist,
>     print all of them. Also, improve the wording of the message.
> 
> compiler/typecheck_clauses.m:
>     Make the same generalization in a pre-diagnostic test, and
>     pass *all* the type assigns to typecheck_error_overload.m, not just
>     the first two.
> 
> compiler/add_pragma.m:
>     Color a diagnostic.
> 
> tests/invalid/bug83.err_exp:
> tests/invalid/coerce_ambig.err_exp:
>     Expect updated diagnostics.

That looks fine.

Peter