pgsql: Remove %error-verbose directive from jsonpath parser

Remove %error-verbose directive from jsonpath parser

None of the other bison parsers contains this directive, and it gives
rise to some unfortunate and impenetrable messages, so just remove it.

Backpatch to release 12, where it was introduced.

Per gripe from Erik Rijkers

Discussion: https://postgr.es/m/ba069ce2-a98f-dc70-dc17-2ccf2a9bf7c7@xs4all.nl

Branch
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REL_15_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/7d9bf589ba840e9f0167a32226ff91a0b50fed95

Modified Files
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src/backend/utils/adt/jsonpath_gram.y       | 1 -
src/test/regress/expected/jsonb_sqljson.out | 2 +-
2 files changed, 1 insertion(+), 2 deletions(-)