pg_tables already includes partitioned tables, so for consistency
pg_indexes should show partitioned indexes.

Author: Suraj Kharage
Reviewed-by: Amit Langote, Michael Paquier
Discussion: https://postgr.es/m/CAF1DzPVrYo4XNTEnc=PqVp6aLJc7LFYpYR4rX=_5pV=wJ2KdZg@mail.gmail.com