lib: Use natural numbers ≥ 1 for canononic names in DFA

lib/dfa.py

@@ -328,7 +328,8 @@ class DFA:
                     queue.append(dfa.transition[actual, character])
                     remain.remove(dfa.transition[actual, character])
 
-            dfa.rename_state(actual, self.bijective26(i))
+            # use self.bijective26(i) for base-26 alphabetic names
+            dfa.rename_state(actual, str(i + 1))
             i += 1
         return dfa