[Proposal] Add Copy Button to Text styled in a specific language

[delvh]

• Gitea version (or commit ref): 1.15.0+dev-347-gc1a80b7d6 and below
• Can you reproduce the bug at https://try.gitea.io:
  • Yes, i.e. https://try.gitea.io/delvh/kanban-test/pulls/10

Description

GitHub has added the feature to copy text styled in a specific language using

    ```<language>
    Some text
    ```

by clicking on a button that on the right-upper corner of the generated area that appears only when the user hovers over that area (see above on the right).
I find that useful as often times the reason why something has been styled in that specific language is to allow for copy and pasting code.

[silverwind]

I plan to follow up with a few copy-related features after #15899.

As for this button, I think I'd prefer if it would copy plain text without fences but I see there may be a necessity to have both options, e.g. "Copy as Markdown" and "Copy as Plain Text". Same goes for the copy feature on lines when viewing a file.

[delvh]

Wait… When is there a necessity to copy text as markdown?

[silverwind]

Ah, no there actually is no copying as markdown, I was just confused by copying above block because it in itself is markdown. We should always copy plain.

[yardenshoham]

I think this has been implemented and can be closed.

[delvh]

Yep, I think I remember that as well.