Add a versionchanged mention to __import__ in regards to negative level values.
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 1cbe34a..2f9a831 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -1506,6 +1506,9 @@
    If you simply want to import a module (potentially within a package) by name,
    use :func:`importlib.import_module`.
 
+   .. versionchanged:: 3.3
+      Negative values for 'level' are no longer supported.
+
 
 .. rubric:: Footnotes