Add comment for the future.

SignalServiceKit/src/Account/CreatePreKeysOperation.swift

@@ -27,6 +27,10 @@ public class CreatePreKeysOperation: OWSOperation {
             self.identityKeyManager.generateNewIdentityKey()
         }
         
+        /// Loki: We don't generate PreKeyRecords here.
+        /// This is because we need the records to be linked to a contact since we don't have a central server.
+        /// It is done automatically when we generate a PreKeyBundle to send to a contact (`generatePreKeyBundleForContact:`).
+        /// You can use `getPreKeyForContact:` to generate one if needed.
         let signedPreKeyRecord = self.primaryStorage.generateRandomSignedRecord()
         signedPreKeyRecord.markAsAcceptedByService()
         self.primaryStorage.storeSignedPreKey(signedPreKeyRecord.id, signedPreKeyRecord: signedPreKeyRecord)