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

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 <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251126081905.7684-2-krzysztof.kozlowski@oss.qualcomm.com>