title: Xcode — quickly open current file in external editor
body: <p>Is it possible to set a keyboard shortcut (or maybe add some menu item somewhere) to open currently edited file in external editor?</p>
  
  <p><em>(Obviously I may do [ (right click in file tree → Show in Finder) / (right click in window title → select containing directory) ] → right click on file → Open With → "the app" — but it's too much steps.)</em></p>