title: Angular Material: Weird suffix fucntionality
body: <p>So I stumbled upon a weird one...
  I am using angular material's form field component to create my forms...
  I noticed that if I use a button inside the mat input field as matSuffix, if I try to submit the form from another field (pressing enter for example)... that field get's the focus and the button (suffix) gets clicked...</p>
  <p>Even wrapping the angular material's example and wrapping it in a form I get the same:
  <a href="https://stackblitz.com/edit/angular-frc7tj?file=app/form-field-prefix-suffix-example.html" rel="nofollow noreferrer">https://stackblitz.com/edit/angular-frc7tj?file=app/form-field-prefix-suffix-example.html</a></p>
  <pre><code>&lt;div class=&quot;example-container&quot;&gt;
    &lt;form&gt;
      &lt;mat-form-field&gt;
        &lt;input
          matInput
          placeholder=&quot;Enter your password&quot;
          [type]=&quot;hide ? 'password' : 'text'&quot;
        /&gt;
        &lt;button
          mat-icon-button
          matSuffix
          (click)=&quot;hide = !hide&quot;
          [attr.aria-label]=&quot;'Hide password'&quot;
          [attr.aria-pressed]=&quot;hide&quot;
        &gt;
          &lt;mat-icon&gt;{{hide ? 'visibility_off' : 'visibility'}}&lt;/mat-icon&gt;
        &lt;/button&gt;
      &lt;/mat-form-field&gt;
  
      &lt;mat-form-field&gt;
        &lt;input
          matInput
          placeholder=&quot;Amount&quot;
          type=&quot;number&quot;
          class=&quot;example-right-align&quot;
        /&gt;
        &lt;span matPrefix&gt;$&amp;nbsp;&lt;/span&gt;
        &lt;span matSuffix&gt;.00&lt;/span&gt;
      &lt;/mat-form-field&gt;
    &lt;/form&gt;
  &lt;/div&gt;
  </code></pre>
  <p>Just type something into the first (password field) and then click into &quot;amount&quot; field and press enter, observe what happens</p>
  <p>the first one gets the focus and the button suffix is clicked....</p>
  <p>how can I prevent this behaviour and actually enforce the normal, expected one (form submission on enter key)?</p>