Broken header link from benchmarks page

Hi :wave: just found a couple broken links on your webpage!

When you are on the [benchmarks page](http://binpa.sh/docs/benchmarks/index.html) if you click the "tutorial" or "docs" header links, they redirect to `/docs/benchmarks/docs/tutorial/` or `/docs/benchmarks/docs/` instead of the appropriate index pages.

Open the benchmarks page at http://binpa.sh/docs/benchmarks/index.html and inspect the "tutorial" and "docs" header links. Compare their destinations with the appropriate index pages, then verify that both links no longer resolve under /docs/benchmarks/docs/.

Written by the indexing model from the issue text.