typo (space-o?)

Doc/library/datetime.rst

@@ -469,7 +469,7 @@ Instance methods:
    Return a 3-tuple, (ISO year, ISO week number, ISO weekday).
 
    The ISO calendar is a widely used variant of the Gregorian calendar. See
-   http://www.phys.uu.nl/ vgent/calendar/isocalendar.htm for a good explanation.
+   http://www.phys.uu.nl/vgent/calendar/isocalendar.htm for a good explanation.
 
    The ISO year consists of 52 or 53 full weeks, and where a week starts on a
    Monday and ends on a Sunday.  The first week of an ISO year is the first