update hacking to mention loglevel notice

svn:r1385

doc/HACKING

@@ -1,4 +1,4 @@
-			 Guide to Hacking Tor
+                        Guide to Hacking Tor
 
 (As of 8 October 2003, this was all accurate.  If you're reading this in
 the distant future, stuff may have changed.)
@@ -398,8 +398,9 @@ the distant future, stuff may have changed.)
       bad thing is either a bug in the code, an attack or buggy
       protocol/implementation of the remote peer, etc. The operator should
       examine the bad thing and try to correct it.
+    NOTICE if it's something the operator will want to know about.
     (No error or warning messages should be expected during normal OR or OP
-      operation. I expect most people to run on -l warn eventually. If a
+      operation. I expect most people to run on -l notice eventually. If a
       library function is currently called such that failure always means
       ERR, then the library function should log WARN and let the caller
       log ERR.)