title: How to translate attributes with the Angular 2 ng-xi18n tool
body: <p>A tag's text can be set for translation like this:
  <code>&lt;h1 i18n&gt;Welcome&lt;/h1&gt;</code></p>
  
  <p>How are attributes like <em>placeholder</em> or <em>label</em> set?
  <code>&lt;input type="text" placeholder="Type your name" /&gt;</code> or
  <code>&lt;button type="submit" label="Send data"&gt;&lt;/button&gt;</code> (library primeng requires to set the button's label like this)</p>
  
  <p>Thanks a lot.</p>