Documentation update

[xandrd]

The documentation page needs formatting fix.

https://nasa.github.io/Kamodo/notebooks/HowtoWriteaModelReader.html#checking-the-variables-requested

[xandrd]

The markdown version formatted correctly (e.g., bullet points and lists):
https://github.com/nasa/Kamodo/blob/master/docs/notebooks/HowtoWriteaModelReader.md