documentation fixing headers and index

[RyanGroneck]

📝 Description

Type: 📝 documentation

This pr does 3 main things:

1. Should fix headings in each documentation notebook (resolving the issue with the model return type doc), making things look nicer.

2. reformat index so that documentation on the website appears in its own separate section

3. change the rotation broadening documentation's name/title to reflect what it is

Also, link issues affected by this pull request by using the keywords: close, closes, closed, fix, fixes, fixed, resolve, resolves or resolved.

📌 Resources

Examples, notebooks, and links to useful references.

🚦 Testing

How did you test these changes?

• Testing pipeline
• Other method (describe)
• My changes can't be tested (explain why)

☑️ Checklist

• I requested two reviewers for this pull request
• I updated the documentation according to my changes
• I built the documentation by applying the build_docs label

Note: If you are not allowed to perform any of these actions, ping (@) a contributor.

[review-notebook-app]

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[tardis-bot]

*beep* *bop*
Hi human,
I ran benchmarks as you asked comparing main (7bddf42) and the latest commit (12a3042).
Here are the logs produced by ASV.
Results can also be downloaded as artifacts here.
Significantly changed benchmarks:

· Benchmark list file .asv/results/benchmarks.json missing!
Use `asv run --bench just-discover` to regenerate benchmarks.json

All benchmarks:

· Benchmark list file .asv/results/benchmarks.json missing!
Use `asv run --bench just-discover` to regenerate benchmarks.json

[RyanGroneck]

I built the website/documentation locally and everything appeared to display as intended.