netlink: specs: rt-route: add C naming info

Add properties needed for C codegen to match names with uAPI headers.

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://patch.msgid.link/20250410014658.782120-7-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/netlink/specs/rt-route.yaml

@@ -2,6 +2,7 @@
 
 name: rt-route
 protocol: netlink-raw
+uapi-header: linux/rtnetlink.h
 protonum: 0
 
 doc:
@@ -11,6 +12,7 @@ definitions:
   -
     name: rtm-type
     name-prefix: rtn-
+    enum-name:
     type: enum
     entries:
       - unspec
@@ -246,6 +248,7 @@ attribute-sets:
 operations:
   enum-model: directional
   fixed-header: rtmsg
+  name-prefix: rtm-
   list:
     -
       name: getroute