Refer to replication origin roident as "ID" in user facing messages and docs

Refer to replication origin roident as "ID" in user facing messages and docs

The table column that stores this is of type oid, but is actually limited
to uint16 and has a different path for creating new values. Some of
the documentation already referred to it as an ID, so let's standardize
on that.

While at it, most format strings already use %u, so for consintency
change the remaining stragglers using %d.

Per suggestions from Tom Lane and Justin Pryzby
Discussion: https://www.postgresql.org/message-id/3437166.1659620465%40sss.pgh.pa.us
Backpatch to v15