BUG #2851: Error in documentation or in code?

The following bug has been logged online:

Bug reference: 2851
Logged by: Gurjeet Singh
Email address: singh(dot)gurjeet(at)gmail(dot)com
PostgreSQL version: 8.2.0
Operating system: Windows XP Professional
Description: Error in documentation or in code?
Details:

The documentation at
http://www.postgresql.org/docs/8.2/interactive/config-setting.html states
that:

Boolean values may be written as ON, OFF, TRUE, FALSE, YES, NO, 1, 0 (all
case-insensitive) or any unambiguous prefix of these.

But the following doesn't work:

postgres=# set enable_seqscan = of;
ERROR: parameter "enable_seqscan" requires a Boolean value
postgres=#

'of' is an unambiguous prefix of OFF, but it clearly doesn't work. Is it the
documentation that needs fix or is it the code?

I tried the following too:

set enable_seqscan = "of"; -- doesn't work
set enable_seqscan = "off"; -- works

BTW, I tried TR, TRU, FA, FAL, FALS, YE. They all work fine.