More user-friendly phrasing

src/templates/register_link.html

 <div class="switch-form">
     <p>{{{ __("Don't have a chat account?") }}}</p>
-    <p><a class="register-account toggle-register-login" href="#converse-register">{{{__("Register an account")}}}</a></p>
+    <p><a class="register-account toggle-register-login" href="#converse-register">{{{__("Create an account")}}}</a></p>
 </div>

src/templates/register_panel.html

 <form id="converse-register" class="pure-form converse-form">
-    <legend>{{{__("Account Registration")}}}</legend>
+    <legend>{{{__("Create your account")}}}</legend>
 
     <label>{{{__("Please enter the XMPP provider to register with:")}}}</label>
     <p class="form-help">{{{help_providers}}} <a href="{{{href_providers}}}" class="url" target="_blank" rel="noopener">{{{help_providers_link}}}</a>.</p>