Fixed URL to the online manual.

README.txt

@@ -72,7 +72,7 @@ Supported Platforms
 Documentation
 
   You can view the current Supervisor documentation online "in html
-  format":http://supervisord.org/manual/ .  This is where you should
+  format":http://supervisord.org/ .  This is where you should
   go for detailed installation and configuration documentation.
 
   XXX We need some way of getting people the entire docs set without