don't use @true and @NULL inside of @code sections

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@54465 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/log.h

@@ -126,7 +126,7 @@ public:
 
     // don't delete logChain directly as this would leave a dangling
     // pointer as active log target, use SetActiveTarget() instead
-    delete wxLog::SetActiveTarget(...something else or @NULL...);
+    delete wxLog::SetActiveTarget(...something else or NULL...);
     @endcode
 
     @library{wxbase}