updated client.count example (current example leads to error 400, QueryParsingException, request does not support [filtered]])

docs/_examples/count.asciidoc

@@ -23,6 +23,7 @@ client.count({
 client.count(
   index: 'index_name',
   body: {
+    query: {
       filtered: {
         filter: {
           terms: {
@@ -31,6 +32,7 @@ client.count(
         }
       }
     }
+  }
 }, function (err, response) {
   // ...
 });