Docs to Markdown support

For support, please use one of the following options:

• Consult the documentation at https://github.com/evbacher/gd2md-html/wiki.
• Contact the Docs to Markdown Google group: https://groups.google.com/g/gd2md-html.
• File a bug atttps://github.com/evbacher/gd2md-html/issues.