Collapses links to JavaScript functions, and removes event attributes from
nodes including children of a collapsed links.

===

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
  <a href="javascript:(() => { alert('uwu') })();">
    <text y="10" onclick="alert('uwu')">uwu</text>
  </a>
</svg>

@@@

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
    <text y="10">uwu</text>
</svg>