bpo-25735: math.factorial doc should mention integer return type (GH-6420)

Doc/library/math.rst

@@ -50,7 +50,7 @@ Number-theoretic and representation functions
 
 .. function:: factorial(x)
 
-   Return *x* factorial.  Raises :exc:`ValueError` if *x* is not integral or
+   Return *x* factorial as an integer.  Raises :exc:`ValueError` if *x* is not integral or
    is negative.
 
 

Misc/NEWS.d/next/Documentation/2018-04-08-19-09-22.bpo-25735.idVQBD.rst

@@ -0,0 +1 @@
+Added documentation for func factorial to indicate that returns integer values