bpo-30737: Update DevGuide links to new URL (GH-3228)

Update old devguide links from https://docs.python.org/devguide to https://devguide.python.org
diff --git a/Misc/python.man b/Misc/python.man
index 385b654..075b974 100644
--- a/Misc/python.man
+++ b/Misc/python.man
@@ -438,7 +438,7 @@
 .br
 Documentation:  https://docs.python.org/
 .br
-Developer resources:  https://docs.python.org/devguide/
+Developer resources:  https://devguide.python.org/
 .br
 Downloads:  https://www.python.org/downloads/
 .br