BUG #17473: Custom range type with timestamp doesn't respect precision

The following bug has been logged on the website:

Bug reference:      17473
Logged by:          John Cwikla
Email address:      cwikla@puzzle.io
PostgreSQL version: 14.2
Operating system:   Debian 14.2-1.pgdg110+1
Description:

Are range types supposed to respect precision? There is no mention of
precision in the documents that I can find, and it doesn't seem to be the
case for timestamps.

psql (14.2 (Debian 14.2-1.pgdg110+1))
SSL connection (protocol: TLSv1.3, cipher: TLS_AES_256_GCM_SHA384, bits:
256, compression: off)
Type "help" for help.

postgres=> CREATE TYPE tstzrange3 AS RANGE ( subtype = timestamp(3) with
time zone);
CREATE TYPE
postgres=> select tstzrange3(NOW(), NULL);
             tstzrange3
------------------------------------
 ["2022-04-29 19:11:31.920322+00",)
(1 row)