title: How to fill arrays of references in a single query
body: <p>I have a schema type Page which has an array of blocks: </p>
  
  <pre class="lang-js prettyprint-override"><code>{
    title: 'Page',
    name: 'page',
    type: 'document',
    fields: [
      ...
      {
        title: 'Blocks',
        name: 'blocks',
        type: 'array',
        of: [
          {type: 'tileGrid'},
          {type: 'otherType'}
        ],
        options: {
          editModal: 'fullscreen'
        }
      }
    ]
  }
  </code></pre>
  
  <p>The type <code>tileGrid</code> has the following fields: </p>
  
  <pre class="lang-js prettyprint-override"><code>{
        title: 'Tiles',
        name: 'tiles',
        type: 'array',
        of:  [{
          type: 'reference',
          to: [
            {type: 'tile'}
          ]
        }]
  }
  </code></pre>
  
  <p>So the <code>tile</code> type is deeply nested <code>page.blocks[].tiles[].tile</code>.
  How can I query <code>page</code> and fill in the <code>tile</code> references in the same query?</p>