title: Replace "Search" button in Wordpress with a Font Awesome font
body: <p>Sorry if this is a stupid question.</p>
  
  <p>I am using Wordpress 4.0 with Bootstrap 3.0 and I have just included Font Awesome via the functions.php file. Everything is working fine (I've used the icons for social media etc).</p>
  
  <p>Now, I want to change the "Search" button in the sidebar to a Font Awesome icon (a search icon, instead of button+text). The code in the file wp-includes/general-template.php looks like this:</p>
  
  <pre><code>    &lt;label&gt;
          &lt;span class="screen-reader-text"&gt;' . _x( '', 'label' ) . '&lt;/span&gt;
          &lt;input type="search" class="search-field" placeholder="' . esc_attr_x( '', 'placeholder' ) . '" value="' . get_search_query() . '" name="s" title="' . esc_attr_x( '', 'label' ) . '" /&gt;
      &lt;/label&gt;
      &lt;input type="submit" class="search-submit" value="'. esc_attr_x( 'Search', 'submit button' ) .'" /&gt;
  </code></pre>
  
  <p>I want just an input field with the icon next to it, like so:</p>
  
  <pre><code>    &lt;label&gt;
          &lt;span class="screen-reader-text"&gt;' . _x( '', 'label' ) . '&lt;/span&gt;
          &lt;input type="search" class="search-field" placeholder="' . esc_attr_x( '', 'placeholder' ) . '" value="' . get_search_query() . '" name="s" title="' . esc_attr_x( '', 'label' ) . '" /&gt;
      &lt;/label&gt;
      &lt;i class="fa fa-search"&gt;&lt;/i&gt;
  </code></pre>
  
  <p>But yeah, this is not working... If I click on the icon, nothing happens. I have tried to put the i class etc into where now is esc_attr_x( 'Search',  but that didn't help either.</p>