add comment about old Orthrus value

EDPlayerJournal/Thargoid.cs

@@ -20,6 +20,7 @@ public class Thargoid {
         // In Update 14.1 the payout for Orthrus has been rebalanced.
         { 30000000, ThargoidVessel.Orthrus },
         { 40000000, ThargoidVessel.Medusa },
+        // This used to be the old payout value for Orthrus
         { 50000000, ThargoidVessel.Orthrus },
         { 60000000, ThargoidVessel.Hydra },
     };