Update Docsy config to fix GitHub links in any submodule docs

[AaronCrawfis]

Today the "Open issue" and "Edit in GitHub" buttons are broken for submodule repos (SDKs, translations, etc.).

We should use the new Docsy capability to cascade the repo link down to fix this: https://www.docsy.dev/docs/adding-content/repository-links/#path_base_for_github_subdir-optional