docs: submitting-patches: Emphasise the requirement to Cc: stable when using Fixes: tag

Clear-up any confusion surrounding the Fixes: tag with regards to the
need to Cc: the stable mailing list when submitting stable patch
candidates.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/20210113163315.1331064-1-lee.jones@linaro.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/process/submitting-patches.rst

@@ -556,6 +556,11 @@ which stable kernel versions should receive your fix. This is the preferred
 method for indicating a bug fixed by the patch. See :ref:`describe_changes`
 for more details.
 
+Note: Attaching a Fixes: tag does not subvert the stable kernel rules
+process nor the requirement to Cc: stable@vger.kernel.org on all stable 
+patch candidates. For more information, please read
+:ref:`Documentation/process/stable-kernel-rules.rst <stable_kernel_rules>`
+     
 .. _the_canonical_patch_format:
 
 The canonical patch format