[donations] Linkify bitcoin

donations.html

@@ -12,7 +12,7 @@
     <td class="subtitle">Donations</td>
 </tr></table>
 
-<p>You can donate via Bitcoin at <code>17EEDY6MuqLQ3jrTeyYaaUXbc6dFaZEYw7</code> .</p>
+<p>You can donate via Bitcoin at <a href="bitcoin:17EEDY6MuqLQ3jrTeyYaaUXbc6dFaZEYw7">17EEDY6MuqLQ3jrTeyYaaUXbc6dFaZEYw7</a> .</p>
 
 <p>You can donate via PayPal here:</p>