pgsql: Remove obsolete RECHECK keyword completely

Remove obsolete RECHECK keyword completely

This used to be part of CREATE OPERATOR CLASS and ALTER OPERATOR
FAMILY, but it has done nothing (except issue a NOTICE) since
PostgreSQL 8.4. Commit 30e7c175b81 removed support for dumping from
pre-9.2 servers, so this no longer serves any need.

This now removes it completely, and you'd get a normal parse error if
you used it.

Reviewed-by: Aleksander Alekseev <aleksander(at)timescale(dot)com>
Discussion: https://www.postgresql.org/message-id/flat/113ef2d2-3657-4353-be97-f28fceddbca1%40eisentraut.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/7da1bdc2c2f17038f2ae1900be90a0d7b5e361e0

Modified Files
--------------
doc/src/sgml/ref/alter_opfamily.sgml | 8 -------
doc/src/sgml/ref/create_opclass.sgml | 8 -------
src/backend/parser/gram.y | 26 +++--------------------
src/include/parser/kwlist.h | 1 -
src/test/isolation/specs/merge-match-recheck.spec | 2 +-
5 files changed, 4 insertions(+), 41 deletions(-)