Wrong handling of longdesc

[pbb72]

Your code copies the content of the longdesc attribute into the desc element.

However, the longdesc attribute shall contain "A link to a more detailed description of the image. Possible values are a URL or an element id" (https://developer.mozilla.org/en-US/docs/Web/HTML/Element/img#attributes:~:text=CSS%20property%20instead.-,longdesc,-Deprecated), while "The desc element provides an accessible, long-text description of any SVG" (https://developer.mozilla.org/en-US/docs/Web/SVG/Element/desc).

Completely different kind of content. The longdesc attribute is a link, not a text.