Reduce namespace length further

src/Memory/borrowed_ptr.cpp

@@ -1 +0,0 @@
-#include "borrowed_ptr.hpp"

src/Memory/borrowed_ptr.hpp

@@ -3,7 +3,7 @@
 
 #include <memory>
 
-namespace ArbUt::Memory {
+namespace ArbUt {
     /// A borrowed pointer is used to indicate a pointer that is not owned by an object, but instead borrowed from
     /// another owning object that is assumed to always be kept alive during the entire lifetime of the borrowing
     /// object.