title: Where to defined code formatting in Xtext
body: <p>I am working in project generated by the xtext project wizard.</p>
  
  <p>On the the Internet there is a lot of examples but I cannot see in which project and the package name the code formatting class must be defined.</p>
  
  <p>Must the class also be register?</p>
  
  <p>PS my Java skills is not very good.</p>