doc: should pg_createsubscriber be grouped as a client application?

pg_createsubscriber is currently grouped as a Server Application:

https://www.postgresql.org/docs/devel/reference-server.html

Contrast the list of Client Applications:

https://www.postgresql.org/docs/devel/reference-client.html

Note that the latter includes pg_basebackup, pg_receivewal, and
pg_recvlogical, which feel generally similar to pg_createsubscriber.

My mental model for Server Applications is "does not make a remote libpq
connection", which does not match what pg_createsubscriber does.

(An indirect effect of this grouping is how packagers split their
-client and -server packages. There are currently a number of
discrepancies among popular packagings, including this one. (I know
that moving files between packages is sometimes difficult, and I don't
necessarily expect that packagers would immediately move this, but at
least the directional guidance could be made more correct.))