Revert "remove links to sections that have not been written yet."

This reverts commit 75b5361178f10f1115470ae21dfd9f8e220b20ae.
Revert "getting started index"

This reverts commit 37169d986c8ddb54b79b3685af31ed453d7de256.
Revert "getting started"

This reverts commit d70fc32d079e766ee90a2e123377007cc219781a.
Revert "rename headings experiment"

This reverts commit 6f1e8437ca5881523bfb1903719edae81bae149f.