pgsql: Unify some error messages - Mailing list pgsql-committers

Unify some error messages

We had essentially the same error in several different wordings.
Unify that.

Branch
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REL_16_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/c672262779833a6b58cf5a4e85a9b76efd660cb7

Modified Files
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src/backend/utils/adt/json.c                       |  4 ++--
src/backend/utils/adt/jsonb_util.c                 |  2 +-
.../ecpg/test/expected/sql-sqljson.stderr          |  6 +++---
src/test/regress/expected/sqljson.out              | 22 +++++++++++-----------
4 files changed, 17 insertions(+), 17 deletions(-)