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_10_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/70f70d7d3f584dbc964348f82a3737ee66f4de01

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           |  3 +++
src/test/regress/sql/event_trigger.sql                |  4 ++++
5 files changed, 28 insertions(+), 5 deletions(-)