title: Birthdate not autofilled in html form
body: <p>I'm using a register formular on my page which should be filled by autofill if the user wants to.
  This works alright for all fields except birthdate with the following html:</p>
  
  <pre><code>&lt;input id="birthDate" name="birthDate" class="select" lang="de" placeholder="dd.mm.yyyy" type="date" date-format="dd.mm.yyyy" value="" autocomplete="bday"&gt;
  </code></pre>
  
  <p><code>bday</code> should be correct according to <a href="https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#attr-fe-autocomplete-bday" rel="noreferrer">https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#attr-fe-autocomplete-bday</a></p>
  
  <p>What am I missing?</p>
  
  <p>I tried to add a new autocomplete address in Chrome, but seems like it doesn't give me the option to add a birthdate in the wizard:
  <a href="https://i.stack.imgur.com/25uwQ.png" rel="noreferrer"><img src="https://i.stack.imgur.com/25uwQ.png" alt="enter image description here"></a></p>
  
  <p>I can't find any information about which fields are supported by which browser unfortunately, so perhaps todays browsers don't even support it yet?</p>