title: User-defined language not applying to specified file types in Notepad++
body: <p>I have created a fairly simple user-defined language in Notepad++, and given it an associated extension. But, when I open files I have named with that extension, nothing happens. No syntax highlighting, or comment highlighting.</p>
  
  <p>Any idea what I have done wrong?</p>
  
  <p>The settings for the extension do not have a leading <code>"."</code>, as specified in the Notepad++ docs.</p>