Draft: Resolve "RGAAv4 enhance 8.9.1 - detect role="presentation""

Closes #473 (closed)

see:

• rgaav4#153
• https://www.numerique.gouv.fr/publications/rgaa-accessibilite/methode/glossaire/#uniquement-a-des-fins-de-presentation

improvements:

<blockquote role="presentation"> ...
<h1 role="presentation"> ...
<h2 role="presentation"> ...
...