Remove doctest for dotproduct().

Author: rhettinger

Doc/library/itertools.rst

@@ -1207,9 +1207,6 @@ which incur interpreter overhead.
     >>> list(ncycles('abc', 3))
     ['a', 'b', 'c', 'a', 'b', 'c', 'a', 'b', 'c']
 
-    >>> dotproduct([1,2,3], [4,5,6])
-    32
-
     >>> data = [20, 40, 24, 32, 20, 28, 16]
     >>> list(convolve(data, [0.25, 0.25, 0.25, 0.25]))
     [5.0, 15.0, 21.0, 29.0, 29.0, 26.0, 24.0, 16.0, 11.0, 4.0]