features/new-in-6.0.x.md: note about internal libraries

docs/features/new-in-6.0.x.md

@@ -391,6 +391,7 @@ receiving
 - CMake compilation and installation support
 - multi-threaded UDP receiving mode
 - several shared memory structures no longer destroyed individually at shut down
+- internal libraries are directly linked to the core
 
 ### kamailio.cfg