In \d and \z, instead of conflating partitioned tables and indexes with
plain ones, set the "type" column and table title differently to make
the distinction obvious.  A simple ease-of-use improvement.

Author: Pavel Stehule, Michaël Paquier, Álvaro Herrera
Reviewed-by: Amit Langote
Discussion: https://postgr.es/m/CAFj8pRDMWPgijpt_vPj1t702PgLG4Ls2NCf+rEcb+qGPpossmg@mail.gmail.com