title: How to get language's full name from languageCode? (e.g: from 'en' to 'English')
body: <p>I'm looking for the dart equivalent of this SO question/answer:
  <a href="https://stackoverflow.com/questions/36061116/get-language-name-in-that-language-from-language-code">Get language name in that language from language code</a></p>
  
  <p>In other words I'd rather avoid going manually one by one of checking if langCode=='en' return 'English' else if langCode == 'fr' return 'French' etc...</p>
  
  <p>I tried looking for possible methods that do this in Locale, Intl, and Localizations classes, to no avail.</p>
  
  <pre><code>DropdownButton&lt;String&gt;(
              items: langCodesList.map((String value) {
                return DropdownMenuItem&lt;String&gt;(
                  child: Text(value),
                  value: value,
                );
              }).toList(),
              hint: Text(Localizations.localeOf(context).languageCode),
            ))
  </code></pre>
  
  <p>I want the DDL to display the full language name.</p>