Fix doctest in factorial_recursive to test correct function

Author: Carraigh

maths/factorial.py

@@ -41,7 +41,7 @@ def factorial_recursive(n: int) -> int:
     https://en.wikipedia.org/wiki/Factorial
 
     >>> import math
-    >>> all(factorial(i) == math.factorial(i) for i in range(20))
+    >>> all(factorial_recursive(i) == math.factorial(i) for i in range(20))
     True
     >>> factorial(0.1)
     Traceback (most recent call last):