pgsql: psql: Add leakproof indicator to \df+, \do+, \dAo+, and \dC+ out

psql: Add leakproof indicator to \df+, \do+, \dAo+, and \dC+ output.

This allows users to determine whether particular functions are
leakproof, and whether the underlying functions used by operators and
casts are leakproof. This is useful to determine whether indexes can
be used in queries on security barrier views or tables with row-level
security policies.

Yugo Nagata, reviewed by Erik Wienhold and Dean Rasheed.

Discussion: https://postgr.es/m/20240701220817.483f9b645b95611f8b1f65da%40sranhm.sraoss.co.jp

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/2355e51110e7c687c125a5958f12a462931de996

Modified Files
--------------
doc/src/sgml/planstats.sgml | 3 ++
doc/src/sgml/ref/psql-ref.sgml | 18 +++++----
doc/src/sgml/rules.sgml | 11 ++++++
src/bin/psql/describe.c | 54 +++++++++++++++++++++------
src/test/regress/expected/psql.out | 75 ++++++++++++++++++++------------------
src/test/regress/sql/psql.sql | 2 +-
6 files changed, 107 insertions(+), 56 deletions(-)