BUG #16850: Inaccuracy in the documentation in the wal_receiver_status_interval parameter description

The following bug has been logged on the website:

Bug reference:      16850
Logged by:          Dmitriy Kuzmin
Email address:      kuzmin.db4@gmail.com
PostgreSQL version: Unsupported/Unknown
Operating system:   any
Description:

The documentation says that setting wal_receiver_status_interval to 0
disable updates of replication status completely. However walreceiver keep
sending status in some cases. For example, when startup has finished
processing WALs and start waiting for more:
https://github.com/postgres/postgres/blob/master/src/backend/access/transam/xlog.c#L12598-L12609
It would be helpful to document in what cases status updates are still being
sent.