Update to the same version info used by the interpreter.
diff --git a/Doc/Makefile b/Doc/Makefile
index 1b54f0b..e4bf438 100644
--- a/Doc/Makefile
+++ b/Doc/Makefile
@@ -66,7 +66,7 @@
 
 # This is the *documentation* release, and is used to construct the file
 # names of the downloadable tarballs.
-RELEASE=2.3
+RELEASE=2.4a0
 
 PYTHON=	   python
 DVIPS=	   dvips -N0 -t $(PAPER)