RE: doc: add missing "id" attributes to extension packaging page

Dear my comrade Brar,

> Thanks, I actually was not aware of this.
> 
> Also, kudos for capturing the missing id and advocating for consistency
> regarding ids even before this is actively enforced. This nurtures my
> optimism that consistency might actually be achieveable without
> everybody getting angry at me because my patch will enforce it.
> 
> Regarding the overlap, I currently try to make it as easy as possible
> for a potential committer and I'm happy to rebase my patch upon request
> or if Kuroda-san's patch gets applied first.

FYI - my patch is pushed [1]. Could you please rebase your patch?
I think it's ok to just remove changes from logical-replication.sgml, ref/alter_subscription.sgml,
and ref/create_subscription.sgml.

[1]: https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=de5a47af2d8003dee123815bb7e58913be9a03f3

Best Regards,
Hayato Kuroda
FUJITSU LIMITED