Update code in factorial

snippets/factorial.md

@@ -13,8 +13,7 @@ Throws an exception if `num` is a negative or a floating point number.
 ```py
 def factorial(num):
   if not ((num >= 0) and (num % 1 == 0)):
-    raise Exception(
-      f"Number( {num} ) can't be floating point or negative ")
+    raise Exception("Number can't be floating point or negative.")
   return 1 if num == 0 else num * factorial(num - 1)
 ```