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: /messages/by-id/ba069ce2-a98f-dc70-dc17-2ccf2a9bf7c7@xs4all.nl

Branch
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REL_12_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/2cf875a4b58d2bc2cce423b3c15fd01250966e40

Modified Files
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src/backend/utils/adt/jsonpath_gram.y | 1 -
src/test/regress/expected/jsonpath.out | 34 +++++++++++++++++-----------------
2 files changed, 17 insertions(+), 18 deletions(-)