Fix typo (GH-22582)

/af/of/s

Automerge-Triggered-By: @Mariatta

Author: st0le

Doc/library/math.rst

@@ -130,7 +130,7 @@ Number-theoretic and representation functions
 
    Return the greatest common divisor of the specified integer arguments.
    If any of the arguments is nonzero, then the returned value is the largest
-   positive integer that is a divisor af all arguments.  If all arguments
+   positive integer that is a divisor of all arguments.  If all arguments
    are zero, then the returned value is ``0``.  ``gcd()`` without arguments
    returns ``0``.