Document change made to number of preallocated integers.

Doc/api/concrete.tex

@@ -156,7 +156,7 @@ There is no \cfunction{PyNone_Check()} function for the same reason.
   Create a new integer object with a value of \var{ival}.
 
   The current implementation keeps an array of integer objects for all
-  integers between \code{-1} and \code{100}, when you create an int in
+  integers between \code{-5} and \code{256}, when you create an int in
   that range you actually just get back a reference to the existing
   object. So it should be possible to change the value of \code{1}.  I
   suspect the behaviour of Python in this case is undefined. :-)