title: How to reference a class in another project?
body: <p>I have a multi-project SBT configuration. I have a class <code>my.AClass</code> in  <code>project1</code>. What should I add to configuration to make scaladoc as follows</p>
  
  <pre><code>/**
   * [[my.AClass]]
   */
  class BClass 
  </code></pre>
  
  <p>in project2 be successfully compiled by <code>sbt project2/doc</code>?</p>