title: How to inherit a template with no ID in Odoo?
body: <p>I am trying to show the date a change was made in a task. To do this, I need to inherit the template of the widget "mail_thread". That template hasn't an id in its definition. This is it:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;template&gt;
  
      &lt;!--
          mail.Widget template used to namespace the css --&gt;
      &lt;t t-name="mail.Root"&gt;
          &lt;div class="oe_mail"&gt;
          &lt;/div&gt;
      &lt;/t&gt;
  
  ...
  
  
                      &lt;span t-att-title="widget.date"&gt;
                          &lt;t t-if="widget.timerelative" t-esc="widget.timerelative"/&gt;
                          &lt;t t-if="!widget.timerelative" t-raw="widget.display_date"/&gt;
                      &lt;/span&gt;
  
  
  
  ...
  
  &lt;/template&gt;
  </code></pre>
  
  <p>In my module, I need to replace the <code>&lt;span&gt;</code> tag in order to show the date.</p>
  
  <p>So, how to inherit that template and replace the  tag?</p>