Update parallelism example

[skrawcz]

Updates parallelism example + some minor typo fixes in docs.

Changes

• changes doc strings
• parallelism example notebook

How I tested this

• locally

Notes

Checklist

• [ ] PR has an informative and human-readable title (this will be pulled into the release notes)
• [ ] Changes are limited to a single goal (no scope creep)
• [ ] Code passed the pre-commit check & code is left cleaner/nicer than when first encountered.
• [ ] Any change in functionality is tested
• [ ] New functions are documented (with a description, list of inputs, and expected output)
• [ ] Placeholder code is flagged / future TODOs are captured in comments
• [ ] Project documentation has been updated if adding/changing functionality.

[github-actions[bot]]

A preview of is uploaded and can be seen here:

✨ https://burr.dagworks.io/pull/431 ✨

Changes may take a few minutes to propagate. Since this is a preview of production, content with draft: true will not be rendered. The source is here: https://github.com/DAGWorks-Inc/burr/tree/gh-pages/pull/431/