title: ignoredWordsInSpellDocumentWithTag, what's the tag?
body: <p>I suspect I'm missing something very obvious, but looking over the NSSpellChecker I'm stumped about what tag I should use in ignoredWordsInSpellDocumentWithTag <em>et al</em>.</p>
  
  <p>My goal is to save and load these from files external to the document itself (the document is a bare text file). But the documentation is very sparse on this topic.</p>