Adopt a 80 character line length for rst files

# 📚 Documentation Request

We should aim for a maximum line length of 80 characters in our documentation rst files. This makes it easier to read in a text editor, easier to make small documentation fixes/tweaks, and does not affect the built html documentation.

Success Criteria:

- Update working practices
- Fix existing docs
- Investigate if we can enforce this in testing.

Start by locating the existing documentation .rst files and the project's testing configuration. Update working practices, reformat existing documentation to a maximum of 80 characters per line, and investigate whether a test can enforce the limit; done means these three success criteria are addressed.

Written by the indexing model from the issue text.