title: href="tel:" and mobile numbers
body: <p>If I use <code>tel:</code> I should write the international phone code, like that.</p>
  
  <pre><code>&lt;a href="tel:+6494461709"&gt;61709&lt;/a&gt;
  </code></pre>
  
  <p>So far, so good, but I can't find information on how to write a cell phone number in an "international" way, if there is one.</p>