Oversight I guess, it's been in the standard for awhile.
Reported-by: Bob Kline <bkline@rksystems.com>
Discussion: https://postgr.es/m/CAGjKmVoP4qVeJgkaBtQ6L46+OLARzmym53uQGhp5COw4wp65yQ@mail.gmail.com
<type>character varying</type>, <type>character</type>,
<type>varchar</type>, <type>date</type>, <type>double
precision</type>, <type>integer</type>, <type>interval</type>,
+ <type>json</type>,
<type>numeric</type>, <type>decimal</type>, <type>real</type>,
<type>smallint</type>, <type>time</type> (with or without time zone),
<type>timestamp</type> (with or without time zone),