pgsql: Remove support for temporal RESTRICT foreign keys

Remove support for temporal RESTRICT foreign keys

It isn't clear how these should behave, so let's wait to implement them
until we are sure how to do it.

This feature was initially added by commit 89f908a6d0a, so it hasn't
been released yet.

Author: Paul A. Jungwirth <pj@illuminatedcomputing.com>
Discussion: https://postgr.es/m/e773bc11-4ac1-40de-bb91-814e02f05b6d%40eisentraut.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/b83e8a2ca2eb381ea0a48e5b2d4e4cdb74febc45

Modified Files
--------------
doc/src/sgml/ref/create_table.sgml             |   4 +
src/backend/commands/tablecmds.c               |   6 +-
src/test/regress/expected/without_overlaps.out | 209 +------------------------
src/test/regress/sql/without_overlaps.sql      | 194 -----------------------
4 files changed, 11 insertions(+), 402 deletions(-)