title: Cross-referencing functions from other submodule in Documenter.jl
body: <p>Given a module hierarchy like</p>
  
  <pre><code>module A
      module B; function foo end; end
      module C
          """
              bar(x)
  
          Like [`foo`](@ref), but more `bar`.
          """
          function bar end
      end
  end
  </code></pre>
  
  <p>How could I cross-reference <code>foo</code> from the docstring of <code>bar</code> using <a href="https://github.com/JuliaDocs/Documenter.jl" rel="noreferrer">Documenter.jl</a>? I have tried <code>A.B.foo</code>, <code>B.foo</code>, and <code>..B.foo</code> without success.</p>