title: What are the new documentation commands available in Xcode 5?
body: <p>One of <a href="https://developer.apple.com/technologies/tools/features.html" rel="noreferrer">Xcode 5's new features</a> is the ability to document your own code with a special comment syntax. The format is similar to doxygen, but appears to only support a subset of <a href="http://www.doxygen.nl/manual/commands.html" rel="noreferrer">those features</a>.</p>
  
  <p>Which commands are supported, and which ones aren't?<br>
  Do any of their usages differ from doxygen?</p>