fix(ops/modules/monorepo-gerrit): fix outdated comment

cl/30249 changed this to Postmark, and it was unconfigured before.

Change-Id: I89eb49dbb8a3cb81135ae01c98379151e32ecd7c
Reviewed-on: https://cl.snix.dev/c/snix/+/30528
Tested-by: besadii
Reviewed-by: Ryan Lahfa <ryan@lahfa.xyz>
Autosubmit: Florian Klink <flokli@flokli.de>

ops/modules/monorepo-gerrit.nix

@@ -139,8 +139,7 @@ in
       # password against the backing OAuth provider.
       auth.gitBasicAuthPolicy = "HTTP";
 
-      # Email sending (emails are relayed via the tazj.in domain's
-      # GSuite currently).
+      # Email sending
       #
       # Note that sendemail.smtpPass is stored in
       # $site_path/etc/secure.config and is *not* controlled by Nix.