Re: [PATCH] Clarify that ssl_groups is for any key exchange groups

Hi Evan,

Thank you for the patch. I was reviewing this as part of the commitfest for
v20.

I agree with the premise, and it's easy to demonstrate. With OpenSSL 3.6.2,
"openssl list -tls-groups" reports MLKEM512, MLKEM768 and MLKEM1024, none
of which are Diffie-Hellman so the old short_desc is simply inaccurate for
a growing set of valid values.

v2 patch no longer applies to master. The config.sgml change is already
upstream (55136e378c6 on master, backpatched as a5112c9b62d on
REL_18_STABLE branch), and the be-secure-openssl.c prototype change has
drifted because init_host_context() gained a hasWarned argument in
9e526a14d7c. "git apply --3way" absorbs both and leaves exactly the
intended +14/-14 across five files, so a straight rebase with the docs
change dropped is all that's needed.

On the remaining rename:
- SSLNamedGroups is consistent with existing style; we already have
SSLCipherList for ssl_ciphers and SSLCipherSuites for ssl_tls13_ciphers, so
mirroring the GUC name exactly isn't the convention.
- Keeping "ssl_ecdh_curve" in map_old_guc_names() is correct. A grep of the
patched tree leaves only that entry and the "versions before 18.0" note in
config.sgml, which are both deliberate.

I built the rebased patch with --with-openssl (OpenSSL 3.6.2) with no
warnings, and "postgres --describe-config" shows the new description.

One minor point in the already-committed docs, "Specifies the named group
to use for TLS key exchange" is singular while a following sentence says
multiple groups can be specified.

Overall the patch looks in a good shape.

Regards,
Surya Poondla