Add notes for continuation of work

Signed-off-by: Fred Boniface <fred@fjla.uk>

src/services/trainService.services2.ts

@@ -54,7 +54,9 @@ export async function findByTrainUid(uid: string, date: Date | string = new Date
 
   let services = filterServices(result) as Service[]
 
-  // Next up is the public stops filter, followed by the PIS filter.
+  // Next up is the public stops filter, the resulting array is used for a PIS search
+  // I can probably write a function that both builds the public stop array and returns
+  // a PIS object - or null.
 }
 
 // Internal Functions: