title: MultiMatch query with Nest and Field Suffix
body: <p>Using Elasticsearch I have a field with a suffix - string field with a .english suffix with an english analyser on it as shown in the following mapping</p>
  
  <pre><code>...
  "valueString": {
      "type": "string",
      "fields": {
          "english": {
               "type": "string",
               "analyzer": "english"
          }
      }
  }
  ...
  </code></pre>
  
  <p>The following query snippet won't compile because <code>ValueString</code> has no <code>English</code> property.</p>
  
  <pre><code>...
  sh =&gt; sh
      .Nested(n =&gt; n
          .Path(p =&gt; p.ScreenData)
              .Query(nq =&gt; nq
                  .MultiMatch(mm =&gt; mm
                      .Query(searchPhrase)
                      .OnFields(
                          f =&gt; f.ScreenData.First().ValueString,
                          f =&gt; f.ScreenData.First().ValueString.english)
                      .Type(TextQueryType.BestFields)
                  )
              )
          )...
  </code></pre>
  
  <p>Is there a way to strongly type the suffix at query time in NEST or do I have to use magic strings?</p>