It doesn't seem to be possible to include external markdown files without using include_file!. By this I mean your file would have to be included in your code hierarchy and it's not possible to have it as a separate hierarchy.

This could be useful for getting-started (even though usually included in the README), debugging-tips, or various tutorials.

A few ideas where this could be used:

• Be able to point rustdoc to some folder with markdown files, and it would render them all for the user to use freely in the code as normal links
• Added as an entry in the left column alongside Module, Structs, Enums, etc. Either a single entry to an index that the user would have to create, or a custom hierarchy that the user would define.