title: main index generated by 'gradle scaladoc' not showing full expanded list of all packages
body: <p>This is a minor annoyance, but nevertheless haunts my dreams. When I generate scaladoc
  and view the main index page I don't see a nice expanded list of all my packages. My colleagues
  who view the documentation have to painstaking click to open packages at each level, and to
  keep them all happy I want to generate a page like this -&gt;</p>
  <pre><code>https://spark.apache.org/docs/latest/api/scala/org/apache/spark/sql/SparkSession.html
  </code></pre>
  <p>If you open that page you will see all the packages nicely pre-expanded in a tree view, like this:</p>
  <pre><code>root
      org
      apache
          spark
              sql
                  api
                  avro
                  catalog
                      etc etc
  </code></pre>
  <p>However, when I use the gradle scaladoc target and open the main index page, I see the packages
  collapsed (with resultant need to click and click).</p>
  <p>Here is the procedure that I use to generate the scaladoc if you want to repro my steps:</p>
  <pre><code>gradle init
      # choose 3/library | 5/scala |  1/groovy | &lt;return&gt; | &lt;return&gt;
  
  # create nested packages
  mkdir src/main/scala/x/foo
  echo 'package x.foo' &gt;&gt; src/main/scala/x/foo/Library.scala
  cat src/main/scala/x/Library.scala &gt;&gt; src/main/scala/x/foo/Library.scala
  mkdir  src/main/scala/x/foo/bar
  echo 'package x.foo.bar' &gt;&gt; src/main/scala/x/foo/bar/Library.scala
  cat src/main/scala/x/Library.scala &gt;&gt; src/main/scala/x/foo/bar/Library.scala
  
  gradlew scaladoc
  </code></pre>
  <p>in browser, view: build/docs/scaladoc/index.html
  notice that we have to click on package 'x' in order to see package 'x.foo', and then click on 'bar' to see
  'x.foo.bar'... This gets old.
  <a href="https://i.stack.imgur.com/auN1e.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/auN1e.png" alt="enter image description here" /></a></p>
  <p>Any tips greatly appreciated !</p>