BUG #14511: Set timezone to local

The following bug has been logged on the website:

Bug reference: 14511
Logged by: Adrian Klaver
Email address: adrian(dot)klaver(at)aklaver(dot)com
PostgreSQL version: 9.5.5
Operating system: Linux openSUSE 42.2
Description:

test=> select version();
version

-------------------------------------------------------------------------------------
PostgreSQL 9.5.5 on x86_64-pc-linux-gnu, compiled by gcc (SUSE Linux)
4.8.5, 64-bit
(1 row)

test=> set timezone = DEFAULT;
SET

test=> set timezone = LOCAL;
ERROR: invalid value for parameter "TimeZone": "local"

test=> set time zone LOCAL;
SET

The docs:

https://www.postgresql.org/docs/9.5/static/sql-set.html

say the last two commands should yield the same result. Not sure if this
error in docs or code.