Update benchmark/README.md

Co-authored-by: Kohei Ueno <[email protected]>

Author: Theo-Steiner

benchmark/README.md

@@ -9,7 +9,7 @@ directory, see [the guide on benchmarks](../doc/contributing/writing-and-running
 
 ## Table of Contents
 
-* [Benchmark Directory Structure](#benchmark-directory-structure)
+* [File tree structure](#file-tree-structure)
 * [Common API](#common-api)
 
 ## File tree structure