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