Fix doubled word.

Doc/api/concrete.tex

@@ -2825,7 +2825,7 @@ instance of \cdata{PyDateTime_DateTime}, including subclasses.
 The argument must not be \NULL{}, and the type is not checked:
 
 \begin{cfuncdesc}{int}{PyDateTime_DATE_GET_HOUR}{PyDateTime_DateTime *o}
-  Return the hour, an an int from 0 though 23.
+  Return the hour, an int from 0 though 23.
   \versionadded{2.4}
 \end{cfuncdesc}