Improve the comment about MOZ_COUNT_CTOR/DTOR, text mostly by bent

no bug, DONTBUILD, landed on a CLOSED TREE

xpcom/glue/nsISupportsImpl.h

@@ -75,8 +75,9 @@ private:
 #define NS_LOG_RELEASE(_p, _rc, _type) \
   NS_LogRelease((_p), (_rc), (_type))
 
-// Note that the following constructor/destructor logging macros
-// should only be used in non-refcounted objects.
+// Note that the following constructor/destructor logging macros are redundant
+// for refcounted objects that log via the NS_LOG_ADDREF/NS_LOG_RELEASE macros.
+// Refcount logging is preferred.
 #define MOZ_COUNT_CTOR(_type)                                 \
 do {                                                          \
   NS_LogCtor((void*)this, #_type, sizeof(*this));             \