title: Why hintEnd not render in formly with material?
body: <p>I try to use the <code>hintEnd</code> from <a href="https://github.com/ngx-formly/ngx-formly/blob/main/src/ui/material/form-field/src/form-field.wrapper.ts#L80" rel="nofollow noreferrer">material with formly option</a>:</p>
  <pre><code>&lt;mat-hint *ngIf=&quot;to.hintEnd as hintEnd&quot; align=&quot;end&quot;&gt;
      &lt;ng-container [ngTemplateOutlet]=&quot;stringOrTemplate&quot; [ngTemplateOutletContext]=&quot;{ content: hintEnd }&quot;&gt;
      &lt;/ng-container&gt;
  &lt;/mat-hint&gt;
  </code></pre>
  <p>In the form structure like this:</p>
  <pre><code>{
      key: &quot;text&quot;,
      type: &quot;input&quot;,
      templateOptions: {
        label: &quot;type something here...&quot;,
        placeholder: &quot;Placeholder&quot;,
        description: &quot;Description&quot;,
        hintEnd: &quot;this is the hint at the end!&quot; // &lt;----- here.
      }
   } 
  </code></pre>
  <p>But in the ui the text is not appear and I got no error.</p>
  <p>Why? what I missing here?</p>
  <p><a href="https://codesandbox.io/s/youthful-clarke-qt1rx?file=/src/app/form.component.ts:648-909" rel="nofollow noreferrer">The example in codesandbox</a></p>