bpo-29535: Remove promize about hash randomization of datetime objects. (GH-15269)

(cherry picked from commit e9c90aa43144b0be1e4e393e8cb549573437a5da)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index fa47bf1..1dd8e42 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -1445,8 +1445,8 @@
 
    .. note::
 
-      By default, the :meth:`__hash__` values of str, bytes and datetime
-      objects are "salted" with an unpredictable random value.  Although they
+      By default, the :meth:`__hash__` values of str and bytes objects are
+      "salted" with an unpredictable random value.  Although they
       remain constant within an individual Python process, they are not
       predictable between repeated invocations of Python.