[ox/std] Add operator-> to SpanIterator

(synced from 963ec5d3f7)

src/ox/std/iterator.hpp

@@ -128,6 +128,10 @@ struct SpanIterator {
 			return operator-=(1);
 		}
 
+		constexpr PtrType operator->() const noexcept {
+			return &m_t[m_offset];
+		}
+
 		constexpr RefType operator*() const noexcept {
 			return m_t[m_offset];
 		}