docs: submitting-patches: encourage direct notifications to commenters

Commenters may not receive new versions of patches via the lists.
Without a directed notification to them they might miss those new
versions.

This is frustrating for the patch developers as they don't receive their
earned Reviewed-by.
It is also frustrating for the commenters, as they might think their
review got ignored or they have to dig up new versions from the archive
manually.

So encourage patch submitters to make sure that all commenters get
notified also when no Reviewed-by was issued yet.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Alexander Dahl <ada@thorsis.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231003-docs-cc-reviewer-v2-1-f93fb946e21e@weissschuh.net