NEWS: rework the description of device naming changes

We really should try to be as precise as possible here. Saying
"your interfaces might be renamed" scares the shit of out people,
for obvious reasons. This change only touches some niche cases
fortunately, let's make this clear.

NEWS

@@ -3,11 +3,24 @@ systemd System and Service Manager
 CHANGES WITH 239 in spe:
 
         * NETWORK INTERFACE DEVICE NAMING CHANGES: systemd-udevd's "net_id"
-          builtin may name network interfaces differently than in previous
-          versions. SR-IOV virtual functions and NPAR partitions with PCI
-          function numbers of 8 and above will be named more predictably, and
-          udev may generate names based on the PCI slot number in some cases
-          where it previously did not.
+          builtin will name network interfaces differently than in previous
+          versions for virtual network interfaces created with SR-IOV and NPAR
+          and for devices where the PCI network controller device does not have
+          a slot number associated.
+
+          SR-IOV virtual devices are now named based on the name of the parent
+          interface, with a suffix of "v<N>", where <N> is the virtual device
+          number. Previously those virtual devices were named as if completely
+          independent.
+
+          The ninth and later NPAR virtual devices will be named following the
+          scheme used for the first eight NPAR partitions. Previously those
+          devices were not renamed and the kernel default (eth<n>) was used.
+
+          "net_id" will also generate names for PCI devices where the PCI
+          network controller device does not have an associated slot number
+          itself, but one of its parents does. Previously those devices were
+          not renamed and the kernel default (eth<n>) was used.
 
         * AF_INET and AF_INET6 are dropped from RestrictAddressFamilies= in
           systemd-logind.service. Since v235, IPAddressDeny=any has been set to