horsegen: generate koka id lists as public

horsegen/spark.kk.template

@@ -13,7 +13,7 @@ extern create-id-table(): vector<int>
   c inline "int32_t arr[] = { {{- range $s := $.Sparks }}{{ $s.ID }},{{ end -}} };\nkk_vector_from_cint32array(arr, (kk_ssize_t){{ $.SparkCount }}, kk_context())"
   js inline "[{{ range $s := $.Sparks }}{{ $s.ID }},{{ end }}]"
 // Vector of all spark IDs in order for easy iterating.
-val all = once(create-id-table)
+pub val all = once(create-id-table)
 
 // Get the name for a spark.
 // The name does not indicate the spark level.