pgsql: Fix JsonExpr deparsing to quote variable names in the PASSING cl

Fix JsonExpr deparsing to quote variable names in the PASSING clause.

When deparsing a JsonExpr, variable names in the PASSING clause were
not quoted. However, since they are parsed as ColLabel tokens, some
variable names require double quotes to ensure that they are properly
interpreted. Fix by using quote_identifier() in the deparsing code.

This oversight was limited to the SQL/JSON query functions
JSON_EXISTS(), JSON_QUERY(), and JSON_VALUE().

Back-patch to v17, where these functions were added.

Dean Rasheed, reviewed by Tom Lane.

Discussion: https://postgr.es/m/CAEZATCXTpAS%3DncfLNTZ7YS6O5puHeLg_SUYAit%2Bcs7wsrd9Msg%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/a93e2a1e25a6d5410abb1446637c4d9a4f24e35d

Modified Files
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src/backend/utils/adt/ruleutils.c | 2 +-
src/test/regress/expected/sqljson_queryfuncs.out | 20 +++++++++++++++++---
src/test/regress/sql/sqljson_queryfuncs.sql | 5 ++++-
3 files changed, 22 insertions(+), 5 deletions(-)