pgsql: Reorganise jsonpath operators and methods

Reorganise jsonpath operators and methods

Various jsonpath operators and methods add various keywords, switch
cases, and documentation entries in some order.  However, they are not
consistent; reorder them for better maintainability or readability.

Author: Jeevan Chalke <jeevan.chalke@enterprisedb.com>
Discussion:
https://www.postgresql.org/message-id/flat/CAM2+6=XjTyqrrqHAOj80r0wVQxJSxc0iyib9bPC55uFO9VKatg@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/283a95da923605c1cc148155db2d865d0801b419

Modified Files
--------------
doc/src/sgml/func.sgml                | 24 +++++-----
src/backend/utils/adt/jsonpath.c      | 82 +++++++++++++++++------------------
src/backend/utils/adt/jsonpath_exec.c | 78 ++++++++++++++++-----------------
src/backend/utils/adt/jsonpath_gram.y | 22 +++++-----
src/include/utils/jsonpath.h          | 25 +++++++----
5 files changed, 119 insertions(+), 112 deletions(-)