Revert "Revert "newer standards prefer nullptr over NULL - this is most of them but there are others too""

This reverts commit 8e2160f33e.

engine/shared/library/sharedFoundation/src/linux/vsnprintf.cpp

@@ -21,7 +21,7 @@
 //
 // Remarks:
 //
-//   If the buffer would overflow, the null terminating character is not written and -1
+//   If the buffer would overflow, the nullptr terminating character is not written and -1
 //   will be returned.
 
 #ifdef _MSC_VER