config: Document cluster_rollover deprecation

Issue: 6128

cluster_rollover is no longer permitted; using it will generate a
warning message and it'll be replaced with cluster_flow

doc/userguide/upgrade.rst

@@ -74,8 +74,8 @@ Deprecations
 - Multiple "include" fields in the configuration file will now issue a
   warning and in Suricata 8.0 will not be supported. See
   :ref:`includes` for documentation on including multiple files.
-- For AF-Packet, the `cluster_rollover` setting is no longer supported. If this is used, a warning
-  message will be printed and `cluster_flow` will be used instead.
+- For AF-Packet, the `cluster_rollover` setting is no longer supported. Configuration settings using ``cluster_rollover``
+  will cause a warning message and act as though `cluster_flow`` was specified. Please update your configuration settings.
 
 Other changes
 ~~~~~~~~~~~~~

suricata.yaml.in

@@ -621,6 +621,7 @@ af-packet:
     #  more info.
     # Recommended modes are cluster_flow on most boxes and cluster_cpu or cluster_qm on system
     # with capture card using RSS (requires cpu affinity tuning and system IRQ tuning)
+    # cluster_rollover has been deprecated; if used, it'll be replaced with cluster_flow.
     cluster-type: cluster_flow
     # In some fragmentation cases, the hash can not be computed. If "defrag" is set
     # to yes, the kernel will do the needed defragmentation before sending the packets.