pgsql: Fix DDL deparse of CREATE OPERATOR CLASS

Fix DDL deparse of CREATE OPERATOR CLASS

When an implicit operator family is created, it wasn't getting reported.
Make it do so.

This has always been missing.  Backpatch to 10.

Author: Masahiko Sawada <sawada.mshk@gmail.com>
Reported-by: Leslie LEMAIRE <leslie.lemaire@developpement-durable.gouv.fr>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Michael Paquiër <michael@paquier.xyz>
Discussion: https://postgr.es/m/f74d69e151b22171e8829551b1159e77@developpement-durable.gouv.fr

Branch
------
REL_12_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/4492e73a66bf88dc7d556a29fde476ba1deb69cb

Modified Files
--------------
src/backend/commands/opclasscmds.c                    | 19 ++++++++++++++-----
src/backend/tcop/utility.c                            |  6 ++++++
.../modules/test_ddl_deparse/expected/opfamily.out    |  1 +
src/test/regress/expected/event_trigger.out           |  5 +++++
src/test/regress/sql/event_trigger.sql                |  4 ++++
5 files changed, 30 insertions(+), 5 deletions(-)