"Copy to clipboard" for Mermaid diagram is broken

Issue

Currently, it is not possible for a user to copy the original source of the rendered mermaid diagram.

Bug / Related feature

1. Copy as GFM

   We support copying markdown source via copy_as_gfm.js helper. It appears to be broken for mermaid diagrams at the moment.

   demo

   

2. "Copy to clipboard" btn

   We recently added "copy to clipboard" button for code blocks. It is displayed for mermaid diagrams as well but it doesn't work.

   demo

   

Fix

TBD