* Add HTML email example
* Add comment about creating `SmtpTransportBuilder`
Add similar comment to `AsyncSmtpTransportBuilder`
* Improve wording and fix typos
* Add file_html example to Cargo.toml
* Update examples/README.md
Co-authored-by: Paolo Barbolini <paolo@paolo565.org>
* Use intra-doc links
* Rename file_html example to basic_html
* Add maud HTML example
* Make CI happy
* Fix CSS
* Fix maud version
Co-authored-by: Paolo Barbolini <paolo@paolo565.org>