title: solr highlighting shows empty result
body: <p>Hi I am new in Solr and using Solr 7.0.0 running in windows 7.
  I created a collection and indexed folder with pdf and html files residing in a folder using the following command:</p>
  
  <pre><code>&gt; java -jar -Dc=guidanceDoc -Dauto example\exampledocs\post.jar M:\Projects\guidance\documents\*
  </code></pre>
  
  <p>If I write a query, I get results. However, if I turn the hl=on, I get a section for highlights without any text.</p>
  
  <p>Here is the query:</p>
  
  <pre><code>http://localhost:8983/solr/guidanceDoc/select?hl.fl=_text_&amp;hl=on&amp;%20q=_text_:"Home%20Use"
  </code></pre>
  
  <p>Here is the highlight part of the result:</p>
  
  <pre><code>"highlighting":{
      "M:\\Projects\\g1\\documents\\gg331681":{},
      "M:\\Projects\\g1\\documents\\gg209337":{},
      "M:\\Projects\\g1\\documents\\ggM380327":{},
      "M:\\Projects\\g1\\documents\\gg470201":{},
      "M:\\Projects\\g1\\documents\\gg507278":{},
      "M:\\Projects\\g1\\documents\\gg073767":{},
      "M:\\Projects\\g1\\documents\\gg380325":{},
      "M:\\Projects\\g1\\documents\\gg484345":{},
      "M:\\Projects\\g1\\documents\\gg259760":{}}}
  </code></pre>
  
  <p>How can I make it work?</p>