bpo-33798: Update csv document about dict order (GH-7490)

(cherry picked from commit 6860629d87d0f6728ff7430453d4900b695adf7b)

Co-authored-by: Andrés Delfino <adelfino@gmail.com>
diff --git a/Doc/library/csv.rst b/Doc/library/csv.rst
index 08b8edc..049537e 100644
--- a/Doc/library/csv.rst
+++ b/Doc/library/csv.rst
@@ -203,9 +203,7 @@
    :class:`writer` instance.
 
    Note that unlike the :class:`DictReader` class, the *fieldnames* parameter
-   of the :class:`DictWriter` is not optional.  Since Python's :class:`dict`
-   objects are not ordered, there is not enough information available to deduce
-   the order in which the row should be written to file *f*.
+   of the :class:`DictWriter` class is not optional.
 
    A short usage example::