docs fix left nav bar

[nathanclevenger]

/docs has some weird behavior and does not look good regarding the left navigation bar

there are capitalization issues, the items are not organized logically, and there are root docs and site objects that don't make sense - the root should be docs ... I think that nextra is picking up on the sites rendering mdx maybe? but most of the structure I think can be managed/resolved from the _meta files

We are running nextra v4 which is brand new and has a breaking API from past versions
https://nextra.site/docs/docs-theme/start

Once we figure this out though, we will be golden