BUG #17139: Invalid input syntax for uuid (politely this time!)

The following bug has been logged on the website:

Bug reference:      17139
Logged by:          Anton Melser
Email address:      anton.melser@outlook.com
PostgreSQL version: 13.3
Operating system:   Linux
Description:

To begin with, thank you for the amazing database that keeps getting better
over the decades!

This is a hopefully far more polite follow-up to BUG #16726. A couple of
decades ago when I first started out I had outbursts like that on public
mailing lists...

Anyway, at the time
(https://www.postgresql.org/message-id/20201119133135.GA31339%40alvherre.pgsql)
Alvaro Herrera suggested the following:

...
ERROR:  invalid input syntax for type uuid:
"{dec3d6c4-c32e-45c6-000-1eae3df44fbf}"
LÍNEA 1: insert into users values ('{dec3d6c4-c32e-45c6-000-1eae3df44...
                                   ^
HINT: Valid UUID values are of the form
'FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF'.
...

Though he pointed out some issues with this, which are definitely valid
ones. However, I still think there might be a way to suggest that there is
something wrong with the *value*, rather than what most naive SQL users like
myself assume when talking about the syntax, which would not include
something inside the value. I can definitely see it is a syntactical (or
maybe morphological?) issue on one level, but I spent more than a few
minutes looking at the docs saying "but I've tried everything they have
suggested and nothing works, my syntax is correct!!!". In my case it was a
bad copy/paste of a UUID (missing the first two characters). When I saw
there was an error with the syntax, I immediately assumed it might not be
liking the single quotes, or the double colons, etc. The aforementioned bug
report was the only thing that got me looking at the actual value I was
trying to query.

Anyway, I apologise for the community on behalf of nozdrum@gmx.de!