Bump Documenter.jl to v1, fix typos

[wheeheee]

• index.md points to the contents page now, as it's the default main page
• updated Documenter compat to "1"
• indented references so they show up in the footnotes, nicely formatted
• fixed typos

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (6c6f4fa) 97.29% compared to head (0a6a52e) 97.46%. Report is 20 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #526 +/- ## ========================================== + Coverage 97.29% 97.46% +0.17% ========================================== Files 18 18 Lines 3105 3080 -25 ========================================== - Hits 3021 3002 -19 + Misses 84 78 -6 ```

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[ViralBShah]

I'm ok with merging this quickly so that it can unlock other doc PRs. I think we can fix anything that is not perfect in a follow-up PR.