docs: submitting-patches: Clarify that removal of Acks needs explanation too

The paragraph mentions only removal of Tested-by and Reviewed-by tags as
action needing mentioning in patch changelog, so some developers treat
it too literally. Acks, as a weaker form of review/approval, should
rarely be removed, but if that happens it should be explained as well.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Jonathan Corbet <[e-mail]>
Message-ID: <[e-mail]>

Documentation/process/submitting-patches.rst

···
 or reviewer, should be added by author to the applicable patches when sending
 next versions.  However if the patch has changed substantially in following
 version, these tags might not be applicable anymore and thus should be removed.
-Usually removal of someone's Tested-by or Reviewed-by tags should be mentioned
-in the patch changelog (after the '---' separator).
+Usually removal of someone's Acked-by, Tested-by or Reviewed-by tags should be
+mentioned in the patch changelog with an explanation (after the '---'
+separator).
 
 A Suggested-by: tag indicates that the patch idea is suggested by the person
 named and ensures credit to the person for the idea: if we diligently credit