[PATCH] doc: clarify AS requirement when VALUES used in a FROM clause

Hi

Per comment here:

https://www.postgresql.org/message-id/178484951486.1225.14869692065642101159%40wrigleys.postgresql.org

the VALUES documentation [*] still claims an AS clause is required
when VALUES is
used in a FROM clause. This has not been the case since PostgreSQL 16
(commit bcedd8f).

[*] https://www.postgresql.org/docs/current/sql-values.html

Attached patch reworks the offending sentence from:

> Note that an AS clause is required when VALUES is used in a FROM clause, just
> as is true for SELECT. It is not required that the AS clause specify names for
> all the columns, but it's good practice to do so.

to:

> If VALUES is used in a FROM clause, it's not necessary to have an AS clause
> specifying names for each column, but it's good practice to do so.

Regards

Ian Barwick