Feature 1468 pyembed docs

[DanielAdriaansen]

Closes #1468

Pull Request Testing

• Describe testing already performed for these changes:
  
  Made changes locally and reviewed on RTD here:
  https://met.readthedocs.io/en/feature_1468_pyembed_docs/Users_Guide/appendixF.html

• Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
  
  Please review the documentation here: https://met.readthedocs.io/en/feature_1468_pyembed_docs/Users_Guide/appendixF.html

• Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [Yes or No]
  Yes

• Do these changes include sufficient testing updates? [Yes or No]
  N/A

• Will this PR result in changes to the test suite? [Yes or No]
  
  If yes, describe the new output and/or changes to the existing output:
  
  I don't think so.

• Please complete this pull request review by 5/7/2021.
  

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[JohnHalleyGotway]

Changes look fine to me. Thanks Dan. I approve.