While exploring ways to tackle this feature, I stumbled on a couple
minor bugs related to `auth-source-pass-extra-query-keywords'.

Because there's no telling when we'll end up with something installable
for this feature, I've gone ahead and isolated the fixes into a separate
patch (0001 in the attached). It's probably safe enough for Emacs 30,
but since the option was introduced back in 29, I'll just install it on
master (unless I hear otherwise in the coming days). Thanks.