Shortcode blocks cover and unsafe rendering

[freudl]

When starting from scratch and designing the cover page one will use the blocks/cover shortcode.

This, however, needs html to render buttons which requires the Goldmark rendering option unsafe.

It would be great if

• the blocks shortcode documentation made me aware of this, or even better
• the sample contained markdown, only, not requiring the Goldmark option
  • to my knowledge, this required an addtional shortcode, e.g. button which takes arguments to define text, color, icon and link

What do you think?