Change the attribute 'name' to 'slot_name' in pg_stat_replication_slots
view to make it clear and that way we will be consistent with the other
places like pg_stat_wal_receiver view where we display the same attribute.

In the passing, fix the typo in one of the macros in the related code.

Bump the catversion as we have modified the name in the catalog as well.

Reported-by: Noriyoshi Shinoda
Author: Noriyoshi Shinoda
Reviewed-by: Sawada  Masahiko and Amit Kapila
Discussion: https://postgr.es/m/CA+fd4k5_pPAYRTDrO2PbtTOe0eHQpBvuqmCr8ic39uTNmR49Eg@mail.gmail.com