title: Can sphinx link to documents that are not located in directories below the root document?
body: <p>I am using Sphinx to document a non-Python project.  I want to distribute <code>./doc</code> folders in each submodule, containing <code>submodule_name.rst</code> files to document that module.  I then want to suck those files into the master hierarchy to create a spec for the entire design.  </p>
  
  <p>I.e.:
  </p>
  
  <pre><code>Project
    docs
      spec
        project_spec.rst
        conf.py
    modules
      module1
        docs
          module1.rst
        src
      module2
        docs
          module2.rst
        src
  </code></pre>
  
  <p>I attempted to include files in the master <code>project_spec.rst</code> document toctree like this:
  </p>
  
  <pre><code>.. toctree::
     :numbered:
     :maxdepth: 2
  
     Module 1 &lt;../../modules/module1/docs/module1&gt;
  </code></pre>
  
  <p>However this error message results:</p>
  
  <blockquote>
    <p>WARNING: toctree contains reference to nonexisting document u'modules/module1/docs/module1'</p>
  </blockquote>
  
  <p>Is it not possible to use <code>../</code> in a document path somehow?</p>
  
  <p>Update: Added conf.py location</p>
  
  <p>Update:
  Other than the include trick below, this is still (2019) not possible. There is an open issue that keeps getting pushed forward: <a href="https://github.com/sphinx-doc/sphinx/issues/701" rel="noreferrer">https://github.com/sphinx-doc/sphinx/issues/701</a></p>