pgsql: Improvements to psql \dAo and \dAp commands

Improvements to psql \dAo and \dAp commands

* Strategy number and purpose are essential information for opfamily operator.
So, show those columns in non-verbose output.
* "Left/right arg type" \dAp column names are confusing, because those type
don't necessary match to function arguments. Rename them to "Registered
left/right type".
* Replace manual assembling of operator/procedure names with casts to
regoperator/regprocedure.
* Add schema-qualification for pg_catalog functions and tables.

Reported-by: Peter Eisentraut, Tom Lane
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/2edc7b27-031f-b2b6-0db2-864241c91cb9%402ndquadrant.com
Backpatch-through: 13

Branch
------
REL_13_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/ae290059e1aa5bc2272a0345184bcf05407f69a4

Modified Files
--------------
src/bin/psql/command.c | 2 +-
src/bin/psql/describe.c | 93 ++++++++++++++++++------------------
src/bin/psql/describe.h | 2 +-
src/test/regress/expected/psql.out | 98 +++++++++++++++++++-------------------
src/test/regress/sql/psql.sql | 2 +-
5 files changed, 98 insertions(+), 99 deletions(-)