Documentation improvements/corrections.

We're always looking for ways to improve documentation.

For this repo, this may be in the README, in the published documentation (RST files), and in docstrings for functions, classes, and modules.

This may include corrections to typos, fact checks, prose clarification, additional sections/topics to help users, etc.

We follow the Google Python Style Guide for docstrings: https://google.github.io/styleguide/pyguide.html

NOTE: While we are certainly open to corrections to inline comments, we subscribe to the idea that code should be self-documenting. In other words, if comments are needed, it is either because the code needs to be written better (broken down into smaller modules, or named better, e.g.), or because there is a "why" or some additional context warranted. Comments should not be added to break up the code or say what the code does. The code breaks itself up and says precisely what it does already.

Review the README, published RST documentation, and function, class, and module docstrings to identify a specific correction or clarification. Check docstrings against the Google Python Style Guide and avoid explanatory inline comments unless they provide essential context; done means a concrete documentation improvement is made and verified for accuracy.

Written by the indexing model from the issue text.