util/AllocatedArray: use `using` instead of `typedef`

src/util/AllocatedArray.hxx

@@ -45,11 +45,11 @@ class AllocatedArray {
 	typedef WritableBuffer<T> Buffer;
 
 public:
-	typedef typename Buffer::size_type size_type;
-	typedef typename Buffer::reference reference;
-	typedef typename Buffer::const_reference const_reference;
-	typedef typename Buffer::iterator iterator;
-	typedef typename Buffer::const_iterator const_iterator;
+	using size_type = typename Buffer::size_type;
+	using reference = typename Buffer::reference;
+	using const_reference = typename Buffer::const_reference;
+	using iterator = typename Buffer::iterator;
+	using const_iterator = typename Buffer::const_iterator;
 
 protected:
 	Buffer buffer{nullptr};