pgsql: Clarify comment about temporal foreign keys

Clarify comment about temporal foreign keys

In RI_ConstraintInfo, period_contained_by_oper and
period_intersect_oper can take either anyrange or anymultirange.

Author: Paul A. Jungwirth <pj@illuminatedcomputing.com>
Discussion:
https://www.postgresql.org/message-id/CA%2BrenyWzDth%2BjqLZA2L2Cezs3wE%2BWX-5P8W2EOVx_zfFD%3Daicg%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/ff30bad7f6f085598e61bb06a8433cb33b3400c7

Modified Files
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src/backend/utils/adt/ri_triggers.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)