Document absolute vs relative relativedelta

Better document difference between adding a relativedelta initialized
with absolute (singular) vs relative (plural) arguments.
diff --git a/docs/examples.rst b/docs/examples.rst
index 815e457..ce52c63 100644
--- a/docs/examples.rst
+++ b/docs/examples.rst
@@ -48,6 +48,15 @@
     >>> TODAY+relativedelta(months=+1, weeks=+1, hour=10)
     datetime.datetime(2003, 10, 24, 10, 0)
 
+Here is another example using an absolute relativedelta.  Notice the use of
+year and month (both singular) which causes the values to be *replaced* in the
+original datetime rather than performing an arithmetic operation on them.
+
+.. doctest:: relativedelta
+
+    >>> NOW+relativedelta(year=1, month=1)
+    datetime(1, 1, 17, 20, 54, 47, 282310)
+
 Let's try the other way around. Notice that the
 hour setting we get in the relativedelta is relative,
 since it's a difference, and the weeks parameter