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
------
REL_14_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/7fd43684fc9e3f2da9c646dea04a531bd6f50cee

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