Demote warnings to notices where appropriate, following the goal that as few "red box" warnings
should clutter the docs as possible. Part 1: stuff that gets merged to Py3k.
diff --git a/Doc/extending/extending.rst b/Doc/extending/extending.rst
index b3ceb94..d052ec2 100644
--- a/Doc/extending/extending.rst
+++ b/Doc/extending/extending.rst
@@ -47,7 +47,7 @@
which pulls in the Python API (you can add a comment describing the purpose of
the module and a copyright notice if you like).
-.. warning::
+.. note::
Since Python may define some pre-processor definitions which affect the standard
headers on some systems, you *must* include :file:`Python.h` before any standard