[PATCH] Simplify the ui-out progress API

[Aaron Merey]

Hi Tom,

On Fri, Mar 4, 2022 at 2:30 PM Tom Tromey <tromey@adacore.com> wrote:
> I noticed that 'progress' is a method on ui-out, but it seems to me
> that it would be better if the only API were via the progress_meter
> class.  This patch makes this change, changing progress to be a method
> on the meter itself.

LGTM. I agree that it's better to use progress_meter for this API.  This
change should be fine even if we were to implement progress handling
in a ui_out derived class.

Aaron