title: ionic change back button icon and text
body: <p>using ionic 3.9.2  </p>
  
  <p><strong>Objective:</strong><br>
  back button in <code>navbar</code> using <code>ios-arrow-back</code> style and "back" with translate pipe</p>
  
  <hr>
  
  <ol>
  <li>with <code>setBackButtonText()</code>, manage to set back button text.<br>
  But it's tedious to do it for every page with getting reference of nav bar, set text after view init.<br>
  Any way to set back button text in template in which can set it like <code>{{ 'back' | translate }}</code>  </li>
  </ol>
  
  <hr>
  
  <ol start="2">
  <li>How to use other icon for back button?  </li>
  </ol>
  
  <p>first try: <code>ion-nav-back-button</code>, prompt <code>ion-nav-back-button</code> not known  </p>
  
  <p>second try:</p>
  
  <pre><code>&lt;ion-buttons start&gt;
    &lt;button ion-button&gt;
      &lt;ion-icon name="ios-arrow-back"&gt;&lt;/ion-icon&gt;
      &lt;p&gt;back&lt;/p&gt;
    &lt;/button&gt;
  &lt;/ion-buttons&gt;
  </code></pre>
  
  <p>However, it's strange that even with <code>start</code>, the button is on right end.  </p>
  
  <p><strong>Playground:</strong><br>
  <a href="https://stackblitz.com/edit/ionic-i3ast3?file=pages%2Fdetails%2Fdetails.component.html" rel="nofollow noreferrer">ionic playground</a></p>
  
  <p>hope to see advice, thanks</p>