The main page should not also be listed in its filesystem location

I have tried making the contents of README_FOR_APP the entry point for my RDoc as follows:

       rdoc.main     = 'doc/README_FOR_APP'                   # define README_FOR_APP as index
       rdoc.rdoc_files.include('doc/README_FOR_APP')

This seems to:

• Generate the contents of README_FOR_APP into index.html in the RDoc output
• Create an RDoc for README_FOR_APP in #{rdoc.rdoc_dir}/doc

The entry point for the RDoc when viewed in the browser is index.html, and the page displayed
contains a link in the 'Pages' block on the left, which points to #{rdoc.rdoc_dir}/doc.

The problem arises when README_FOR_APP itself contains links to other RDoc files generated.
I can get these to work with the appropriate leading relative path in either of the two cases, but not both,
since the index.html and doc/README_FOR_APP are in different dirs.

I have found a workaround in placing README_FOR_APP in Rails.root and removing the leading
'doc' entries from the config:

       rdoc.main     = 'README_FOR_APP'                   # define README_FOR_APP as index
       rdoc.rdoc_files.include('README_FOR_APP')

... but it should not be necessary to pollute Rails.root with docs ...

Start by reproducing the RDoc configuration using doc/README_FOR_APP as both rdoc.main and an included file, then trace how the main page and Pages block are generated. Compare that output with the workaround using README_FOR_APP at Rails.root. Done means the configured main page is not also listed under its filesystem location and links work from the generated index.