fix notes about password encryption in pg_authid docs

Nathan Bossart <nathandbossart@gmail.com>

From: Nathan Bossart <nathandbossart@gmail.com>

To: pgsql-hackers@postgresql.org

Date: 2025-06-02T14:16:10Z

Lists: pgsql-hackers

I noticed that the docs for the pg_authid catalog still indicate that
passwords might be stored "unencrypted," which hasn't been possible since
commit eb61136.  The attached patch attempts to fix that.  If acceptable,
I'd back-patch it to all supported versions.

-- 
nathan

Commits

doc: Remove notes about "unencrypted" passwords.
- f9b1192190aa 18.0 landed
- efb3f16e0d34 15.14 landed
- 6e71b7a39646 16.10 landed
- 49584901ecc4 14.19 landed
- 1a7968ac5f89 13.22 landed
- 002938f15c63 17.6 landed
Remove support for password_encryption='off' / 'plain'.
- eb61136dc75a 10.0 cited