Re: list of extended statistics on psql

Hi Julien!

> Thanks also for the documentation and regression tests. This overall looks
> good, I just have a two comments:

Thank you for reviewing the patch! :-D

> - there's a whitespace issue in the documentation part:
>
> add_list_extended_stats_for_psql_by_dX_command.patch:10: tab in indent.
> <varlistentry>
> warning: 1 line adds whitespace errors.

Oops, I forgot to use "git diff --check". I fixed it.

> - You're sorting the output on schema, table, extended statistics and columns
> but I think the last one isn't required since extended statistics names are
> unique.

You are right.
The sort key "columns" was not necessary so I removed it.

Attached new patch includes the above two fixes:

- Fix whitespace issue in the documentation part
- Remove unnecessary sort key from the query
(ORDER BY 1, 2, 3, 4 -> ORDER BY 1, 2, 3)

Thanks,
Tatsuro Yamada