title: Elasticsearch 7.x case insensitive sorting using normalizer
body: <p>I am using elasticsearch 7.5 and NEST client.</p>
  
  <p>I want to sort a query, and as you know, by default does A..Za..z. I want it to be case insensitive.</p>
  
  <p>I am trying to use a normalizer as is explained <a href="https://discuss.elastic.co/t/case-insensitive-sort-doesnt-work/143192/7" rel="nofollow noreferrer">here</a></p>
  
  <pre><code>PUT /testindex
  {
    "settings": {
       "analysis": {
         "normalizer": {
           "case_insensitive": {
              "filter": "lowercase"
           }
          }
         }
       }
  }
  </code></pre>
  
  <p>And then I could use it in the mapping:</p>
  
  <pre><code>PUT /testindex/_mapping/testmapping
  {
    "properties": {
      "Id": {
      "type": "keyword"
      },
      "Name": {
        "type": "text",
        "fields": {
          "keyword": {
            "type": "keyword",
            "normalizer": "case_insensitive"
          }
        }
       }
     }
  }
  
  </code></pre>
  
  <p>The problem it comes when I try to do it on the C# NEST client:</p>
  
  <pre><code>client.Indices.Create("testindex", e =&gt; e
                  .Settings(s =&gt; s
                      .Analysis(a =&gt; a
                          .Normalizers(n =&gt; n.Custom("case_insensitive",c =&gt; c.Filters("lowercase")))))
                  .Map(m =&gt; m
                      .Properties(p =&gt; p
                         .Text(st =&gt; st.Name("Name")
                         **.NORMALIZER**)))
              );
  </code></pre>
  
  <p>There is no way to add the normalizer the Name property field.</p>
  
  <p>Any ideas? Another way to do it efficiently? </p>
  
  <p>Thanks a million.</p>