title: MongoDB: Case insensitive and accent insensitive
body: <p>I am looking for string <code>"JESÚS"</code> but only returns the document with the specified string, I need the search to ignore the accents and capital letters.</p>
  
  <p>I am using C# and mongodb driver.</p>
  
  <p>I have two documents saved in my mongodb:</p>
  
  <pre><code>_id:5d265f3129ea36365c7ca587
  TRABAJADOR:"JESUS HERNANDEZ DIAZ"
  
  _id:5d265f01db86a83148404711
  TRABAJADOR:"JESÚS HERNÁNDEZ DÍAZ"
  </code></pre>
  
  <p>In visual c# with mongo driver:</p>
  
  <pre><code>var filter = Builders&lt;BsonDocument&gt;.Filter.Regex("TRABAJADOR", new BsonRegularExpression(string.Format(".*{0}.*", "JESÚS"), "i"));
  
  var result = collection.Find(filter, new FindOptions() { Collation = new Collation("es", strength: CollationStrength.Primary, caseLevel:true) }).ToList();
  
  output = JsonConvert.SerializeObject(result);
  return output;
  
  </code></pre>
  
  <p>If I search for <code>"JESÚS"</code>, actual output:</p>
  
  <pre><code>_id:5d265f01db86a83148404711
  TRABAJADOR:"JESÚS HERNÁNDEZ DÍAZ"
  </code></pre>
  
  <p>But actually I am expecting following output:</p>
  
  <pre><code>_id:5d265f3129ea36365c7ca587
  TRABAJADOR:"JESUS HERNANDEZ DIAZ"
  
  _id:5d265f01db86a83148404711
  TRABAJADOR:"JESÚS HERNÁNDEZ DÍAZ"
  </code></pre>