Empty title change rendering of siblings

I'm about to merge an fixup that may start including empty <title>s in manual, in an effort to translations can be build able for more time, particully at times that doc-en is being heavy updated.

The fixup <title></title><simpara>%failed xi:xinclude%</simpara> (empty title) is saved on .manual.xml as:

<refsect1 role="parameters">
 <title/>
 <simpara>%failed xi:xinclude%</simpara>
</refsect1

and is rendered by php phd/render.php --format bigxhtml as:

<div class="refsect1 parameters" id="refsect1-function.bcdivmod-parameters">
  <h3 class="title"><p class="simpara">%failed xi:xinclude%</p></h3>
</div>

Instead of:

<div class="refsect1 parameters" id="refsect1-function.bcdivmod-parameters">
  <h3 class="title"></h3>
  <p class="simpara">%failed xi:xinclude%</p>
</div>

In other words, empty <title> causes their siblings to be rendered inside the title, instead of around it. I'm worried that this can swallows entire sections inside titles. In the meanwhile, and to workaround this, I'm placing some placeholder texts in fixup titles, but these ends rendered in manual.

Reproduce the issue with php phd/render.php --format bigxhtml using the shown .manual.xml structure containing an empty <title/> and a sibling . Trace the bigxhtml rendering path and verify that the completed output keeps the outside the empty

element.