title: How to use autocorrect and spell check in iOS custom keyboard?
body: <p>I have developed a custom keyboard and I need to add auto-correct and spell-check functionality to it. 
  Using UITextChecker for word completions and guesses does not give very good results and is quite different from the native keyboard. 
  For e.g. typing "there" suggests </p>
  
  <p>Word Completions : [Thereabout, Thereabouts, Thereafter, Thereat, Thereby, Therefor, Therefore, Therefrom, Therein, Thereof, Thereon, Thereto, Thereunder, Thereunto, Thereupon, Therewith, There].</p>
  
  <p>Word guesses : ["Their", "Three", "Thera", "Therm", "Theme", "These", "Where", "Here", "Thee", "Theres"].</p>
  
  <p>While the native keyboard suggests totally different results.</p>
  
  <p>Is there a different way to add efficient auto-correct and spell-check functionality?</p>