[FEATURE] Maintain relative markdown links

[spike-rabbit]

Overview of the feature

We use markdown files to document much of our code and use relative links to link between the markdown files. These relative links work great in bitbucket or github, but after documentation generation the links are broken due to .md files now being .html files. It would be great to change these relative links during generation.

Motivation for or Use Case

Without this, we have to decide if we want links to work in the documentation generation or when viewing from the repository, but we can't get both without an additional processing step outside of compodoc.

Related issues

This is a reopening of #149

[vogloblinsky]

Do you have an example please ?

[spike-rabbit]

Thank you for looking into this @vogloblinsky .
I created a reproduction repo on github. I splitted it into a few commits, so that you identify the relevant changes.

Once you had time to look into this, please let me know if this is something you consider as a useful feature and if you would implement it or an upstream contribution is neccessary.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.