Swap for-loops to increase performance

This method is faster if the first for-loop contains fewer items.
Since the function is called with, typically, `dist2` having less items, let's loop over `dist2` first. This makes the entire program 10% faster.

worlds/yachtdice/Rules.py

@@ -108,8 +108,8 @@ def dice_simulation_strings(categories, num_dice, num_rolls, fixed_mult, step_mu
     # defaultdict is a dict where you don't need to check if an id is present, you can just use += (lot faster)
     def add_distributions(dist1, dist2):
         combined_dist = defaultdict(float)
-        for val1, prob1 in dist1.items():
-            for val2, prob2 in dist2.items():
+        for val2, prob2 in dist2.items():
+            for val1, prob1 in dist1.items():
                 combined_dist[val1 + val2] += prob1 * prob2
         return dict(combined_dist)