Add example augmented radix tree figure

Internal.h

@@ -435,6 +435,10 @@ struct ReferenceImpl {
 
 using Key = ConflictSet::Key;
 
+inline Key operator"" _s(const char *str, size_t size) {
+  return {reinterpret_cast<const uint8_t *>(str), int(size)};
+}
+
 [[maybe_unused]] static Key toKey(Arena &arena, int n) {
   uint8_t *buf = new (arena) uint8_t[sizeof(n)];
   memcpy(buf, &n, sizeof(n));