[Backport 0.9] Typo on docs script won't load versioned index of content
When loading the index JSON file from alternates version of the docs, there's an extra /
on the address which causes the request to be blocked by the server.
- How is now: https://stackgres.io/doc/1.1//index.json
- How it should be: https://stackgres.io/doc/1.1/index.json