Fix documentation to include possible Exception (#94818)

Author: yourlefthandman

Doc/library/datetime.rst

@@ -1370,8 +1370,8 @@ Instance methods:
    time and this method relies on the platform C :c:func:`mktime`
    function to perform the conversion. Since :class:`.datetime`
    supports wider range of values than :c:func:`mktime` on many
-   platforms, this method may raise :exc:`OverflowError` for times far
-   in the past or far in the future.
+   platforms, this method may raise :exc:`OverflowError` or :exc:`OSError`
+   for times far in the past or far in the future.
 
    For aware :class:`.datetime` instances, the return value is computed
    as::