Add documentation for tourist trade bug in King

- really bad pollution can get positive money from tourists
- fix issue in python implementation, other implementations still lack
  it

53_King/python/king.py

@@ -61,7 +61,7 @@ class GameState:
         return self.countrymen - self.population_change
 
     def sell_land(self, amount: int) -> None:
-        assert amount < self.farmland
+        assert amount <= self.farmland
         self.land -= amount
         self.rallods += self.land_buy_price * amount
 
@@ -126,7 +126,9 @@ class GameState:
     def handle_tourist_trade(self) -> None:
         V1 = int(self.settled_people * 22 + random() * 500)
         V2 = int((INITIAL_LAND - self.land) * 15)
-        tourist_trade_earnings = int(V1 - V2)
+        tourist_trade_earnings = 0
+        if V1 > V2:
+            tourist_trade_earnings = V1 - V2
         print(f" YOU MADE {tourist_trade_earnings} RALLODS FROM TOURIST TRADE.")
         if V2 != 0 and not (V1 - V2 >= self.tourism_earnings):
             print("   DECREASE BECAUSE ")