Change admonitions

[jukent]

With the new sphinx theme, admonitions are called like

```{admonition} Info
:class: tip

In the above code example, we are extract ...

The HTML <div> ... version was causing the issues. This is isolated to these two files and doesn't require an overall theme adjustment.

Closes https://github.com/ProjectPythia/sphinx-pythia-theme/issues/64

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👋 Thanks for opening this PR! The Cookbook will be automatically built with GitHub Actions. To see the status of your deployment, click below. 🔍 Git commit SHA: 287cae81d531578df28039e5bb94380489c496b8 ✅ Deployment Preview URL: https://ProjectPythia.github.io/pythia-foundations/_preview/469

[brian-rose]

Link checker failure is unrelated, but we need to address that too.

[jukent]

Link checker failure is unrelated, but we need to address that too.

I just fixed one link, but there are two more that are failing to pass link-checker that aren't broken.

(core/datetime/datetime: line 200010) broken    https://ghrc.nsstc.nasa.gov/uso/ds_docs/vaiconus/vaiconus_dataset.html#a6 - HTTPSConnectionPool(host='ghrc.nsstc.nasa.gov', port=443): Max retries exceeded with url: /uso/ds_docs/vaiconus/vaiconus_dataset.html (Caused by NewConnectionError('<urllib3.connection.HTTPSConnection object at 0x7f5cbcc04830>: Failed to establish a new connection: [Errno 101] Network is unreachable'))
(core/datetime/datetime: line 200006) broken    https://ghrc.nsstc.nasa.gov/uso/ds_docs/vaiconus/vaiconus_dataset.html - HTTPSConnectionPool(host='ghrc.nsstc.nasa.gov', port=443): Max retries exceeded with url: /uso/ds_docs/vaiconus/vaiconus_dataset.html (Caused by NewConnectionError('<urllib3.connection.HTTPSConnection object at 0x7f5cbcd4ec60>: Failed to establish a new connection: [Errno 101] Network is unreachable'))
build finished with problems, 43 warnings.