title: Haystack Whoosh Spelling Suggestion too greedy
body: <p>This questions is about Django Haystack, with Whoosh backend.
  I would like to use spelling suggestion in my search. The problem is that it is suggesting TOO much.</p>
  
  <p>Say I have two models:
  Apples and Oranges.</p>
  
  <p>If I have somethine like this:</p>
  
  <pre><code>result = SearchQuerySet().models(Apples).filter(
      content=escaped_value).spelling_suggestion(escaped_value)
  </code></pre>
  
  <p>it will actually LOOK into Oranges model and return a spelling suggestion from that! It seems like <em>models(Apples)</em> restriction does not work.</p>
  
  <p>I have indexes setup for both models, with "text" attribute as document=True. My spelling is ON. I am using Whoosh as backend.</p>