fond blanc un petit peu trop petit, fix

prive/themes/spip/images/media-audio-xx.svg

 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64" width="64" height="64">
-  <path fill="#fff" d="M8 11h48v42H8z" />
+  <path fill="#fff" d="M8 8h48v48H8z" />
   <path fill="#119914" d="M48 18.5l-15.1-6.4c-.2-.1-.4-.1-.6 0h-.1l-.1.1v.1c0 .1-.1.1-.1.2v27.9c-2.5-3.1-7-3.5-10.1-1-3.1 2.5-3.5 7-1 10.1 2.5 3.1 7 3.5 10.1 1 1.7-1.4 2.7-3.4 2.6-5.6V24.2l14 5.9h.3c.4 0 .8-.4.8-.8V19.2c0-.4-.3-.7-.7-.7z" id="Calque_5"/>
   <path fill="#119914" d="M33.5 41.9h-3.4V11l3.4 1.3z"/>
   <path fill="#119914" d="M2 5.3C2 3.5 3.5 2 5.3 2h53.4C60.5 2 62 3.5 62 5.3v53.4c0 1.8-1.5 3.3-3.3 3.3H5.3C3.5 62 2 60.5 2 58.7V5.3zm6.7 3.4v46.7h46.7V8.7H8.7z"/>

prive/themes/spip/images/media-video-xx.svg

 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64" width="64" height="64">
-  <path fill="#fff" d="M8 11h48v42H8z" id="Calque_3"/>
+  <path fill="#fff" d="M8 8h48v48H8z" />
   <path fill="#a37800" d="M2 5.3C2 3.5 3.5 2 5.3 2h53.4C60.5 2 62 3.5 62 5.3v53.4c0 1.8-1.5 3.3-3.3 3.3H5.3C3.5 62 2 60.5 2 58.7V5.3zm6.7 3.4v46.7h46.7V8.7H8.7z"/>
   <path fill="#a37800" d="M24.6 16.9l20.6 13.7c.8.5 1 1.6.5 2.3-.1.2-.3.3-.5.5L24.6 47.2c-.8.5-1.8.3-2.3-.5-.2-.3-.3-.6-.3-.9V18.3c0-.9.8-1.7 1.7-1.7.3 0 .7.1.9.3z" id="Calque_5"/>
 </svg>
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