BUG #14244: wrong suffix for pg_size_pretty()

The following bug has been logged on the website:

Bug reference: 14244
Logged by: Thomas Berger
Email address: thomas(dot)berger(at)1und1(dot)de
PostgreSQL version: 9.5.3
Operating system: any
Description:

pg_size_pretty uses the suffix "kB" (kilobyte, 10^3 byte), but the returned
value is "KB", or "KiB" ( kibibyte, 2^10 byte). This is missleading and
should be fixed. See also https://en.wikipedia.org/wiki/Kibibyte

=# select pg_size_pretty(1024000::bigint);
pg_size_pretty
----------------
1000 kB