title: Issues with NSSpellChecker and setting words to ignore
body: <p>I'm trying to implement a function to check the names of some subfolders for spelling.
  I have a test function, shown below.
  The folder names are in a <code>[String]</code> called listOfFolders.</p>
  <p>I'm using <code>guesses(forWordRange:in:language:inSpellDocumentWithTag:)</code> and it seems to work in that it does show me recommended spellings of words that seem to be spelled incorrectly, however I want to ignore some words – and that doesn't seem to work.</p>
  <pre><code>    func check() {
          let words = listOfFolders.joined(separator: &quot; &quot;)
          let spellChecker = NSSpellChecker.shared
          spellChecker.setIgnoredWords([&quot;Stills&quot;, &quot;Video&quot;, &quot;HEIC&quot;, &quot;JPG&quot;, &quot;EIP&quot;, &quot;ARW&quot;, &quot;IIQ&quot;, &quot;NEF&quot;, &quot;FFF&quot;, &quot;CR2&quot;, &quot;CR3&quot;, &quot;RAF&quot;, &quot;DNG&quot;], inSpellDocumentWithTag: 0)
          for word in listOfFolders {
              let w = word
              let start = 0
              let end = w.count
              let range : NSRange = NSRange(location: start, length: end)
              let g = spellChecker.guesses(forWordRange: NSRange.init(location: start, length: end), in: String(w), language: nil, inSpellDocumentWithTag: 0)
              print(&quot;w: \(w)&quot;)
              print(&quot;g: \(g)&quot;)
          }
      }
  </code></pre>