title: Where are `kAFAssistantErrorDomain` codes documented?
body: <p>I'm trying to work with <code>SFSpeechRecognizer</code> on macOS.</p>
  
  <p>I'm getting error messages such as:</p>
  
  <pre><code>ERROR in Dictation.swift: Error Domain=kAFAssistantErrorDomain Code=209 "(null)"
  ERROR in Dictation.swift: Error Domain=kAFAssistantErrorDomain Code=1 "(null)"
  </code></pre>
  
  <p>How to interpret these error messages?  I cannot find the codes enumerated anywhere in the documentation.</p>