Improve documentation

[madsmtm]

From the Rust API guidelines:

• Crate level docs are thorough and include examples (C-CRATE-DOC)
• All items have a rustdoc example (C-EXAMPLE)
• Examples use ?, not try!, not unwrap (C-QUESTION-MARK)
  • The uses of .unwrap() are justified.
• Function docs include error, panic, and safety considerations (C-FAILURE)

I think there are some clippy/cargo-check features to turn on that can help with ensuring this.