netlink: specs: rt-route: add route notifications

Declare the RTM_NEWROUTE and RTM_DELROUTE notifications and the route
multicast groups, so that generated clients can subscribe to route
changes. Both notifications reuse the getroute reply attributes.

Signed-off-by: Yuyang Huang <sigefriedhyy@gmail.com>
Link: https://patch.msgid.link/20260808005642.26901-8-sigefriedhyy@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Documentation/netlink/specs/rt-route.yaml

@@ -322,3 +322,22 @@ operations:
         request:
           value: 25
           attributes: *all-route-attrs
+    -
+      name: newroute-ntf
+      doc: Notification about a created route.
+      value: 24
+      notify: getroute
+    -
+      name: delroute-ntf
+      doc: Notification about a deleted route.
+      value: 25
+      notify: getroute
+
+mcast-groups:
+  list:
+    -
+      name: rtnlgrp-ipv4-route
+      value: 7
+    -
+      name: rtnlgrp-ipv6-route
+      value: 11