warn about some members of the commands module
diff --git a/Doc/library/commands.rst b/Doc/library/commands.rst
index 177710b..c3f7710 100644
--- a/Doc/library/commands.rst
+++ b/Doc/library/commands.rst
@@ -42,7 +42,13 @@
 
    .. deprecated:: 2.6
       This function is nonobvious and useless, also the name is misleading in the
-      presence of :func:`getstatusoutput`.
+      presence of :func:`getstatusoutput`.  It is removed in 3.x.
+
+.. warning::
+
+   Two undocumented functions in this module, :func:`mk2arg` and :func:`mkargs`
+   are removed in 3.x.
+
 
 Example::