All the examples of MailMerge.Execute( string, object) show you
passing plain strings, which is quite limited in its usefulness.
I previously passed Editor.Document objects successfully, but since
the editor is discontinued we’ve replaced it with our own Rich Text
Editor. I’m able to read the RTF into an Aspose.Document just fine,
but when the Document is passed to MailMerge.Execute it just displays
the type name in my document.
So, what object types does MailMerge.Execute( string, object) support
that will preserve formatting?