Community Backlog: copy snippet to the clipboard

[Deleplace]

When contributing in the "Missing Demo" section, the user typically wants to copy the snippet and paste it into an external Playground site.

Current UI

There is no "copy code" button. The user must select it manually with the mouse, then copy.

Desired UI

A prominent "Copy" button.

[Deleplace]

The "Copy snippet to the clipboard" button already exists in the Idiom detail page. Something similar shall be fine.