pgsql: Remove dubious warning message from SQL/JSON functions

Remove dubious warning message from SQL/JSON functions

There was a warning that FORMAT JSON has no effect on json/jsonb
types, which is true, but it's not clear why we should issue a warning
about it.  The SQL standard does not say anything about this, which
should generally govern the behavior here.  So remove it.

Discussion: https://www.postgresql.org/message-id/flat/dfec2cae-d17e-c508-6d16-c2dba82db486%40eisentraut.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/881cd9e581c2c40023f82edcd1cd2335691b78f2

Modified Files
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src/backend/parser/parse_expr.c       | 5 -----
src/test/regress/expected/sqljson.out | 6 ------
2 files changed, 11 deletions(-)