pgsql: Doc: recommend "psql -X" for restoring pg_dump scripts.

Doc: recommend "psql -X" for restoring pg_dump scripts.

This practice avoids possible problems caused by non-default psql
options, such as disabling AUTOCOMMIT.

Author: Shinya Kato <Shinya11.Kato@oss.nttdata.com>
Reviewed-by: Robert Treat <rob@xzilla.net>
Discussion: https://postgr.es/m/96ff23a5d858ff72ca8e823a014d16fe@oss.nttdata.com
Backpatch-through: 13

Branch
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REL_14_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/4106942f004fdd789ea4b35be0585c1f8268744d

Modified Files
--------------
doc/src/sgml/backup.sgml         | 22 ++++++++++++++--------
doc/src/sgml/ref/pg_dump.sgml    | 10 +++++++++-
doc/src/sgml/ref/pg_dumpall.sgml | 15 +++++++++++++--
3 files changed, 36 insertions(+), 11 deletions(-)