util/DereferenceIterator: fix static_cast in operator->()

src/util/DereferenceIterator.hxx

@@ -61,7 +61,7 @@ public:
 	}
 
 	pointer operator->() const noexcept {
-		return static_cast<reference>(*original.IT::operator->());
+		return static_cast<pointer>(*original.IT::operator->());
 	}
 
 	auto &operator++() noexcept {