Incorrect GetDatum() macros not match with SQL function types

Hi all,
(Aleksander in CC, who has authored some of them in pageinspect.)

While looking at the business in [1], I have noticed a bunch of areas
in the code base where the *GetDatum() macros used do not match with
the data type of the SQL functions they relate to, leading me to the
attached.

I am creating a new thread for clarity, as the patch was hidden in the
middle of a different discussion.

When it comes to the numbers touched here, the signedness should not
matter, so this most likely a cleanup worth doing for v20, not v19.

Thanks,

[1]: https://www.postgresql.org/message-id/CAJ7c6TMcGu8qmRe1gZfJ-gOzVnZq-t=fwn-UuyStx1w6ZyydMw@mail.gmail.com
--
Michael