Add copy to clipboard button in code snippets

[DavG25]

Add customized version (that works with Gradio and this extension) of highlightjs-copy to show a button in each code snippet that copies code

Requested in #1

[Starlento]

Extension commit ID: 6be5366
webui commit ID: 19f78684e6d32d43cd5ce3ae82d6f2216421b9ae
environment: WSL2

I tested the function. Overall, this works well. Thank you very much for your update.
One trival problem is that if code snippet is only one line, the button seems too large.

[DavG25]

One trival problem is that if code snippet is only one line, the button seems too large.

Thanks for pointing that out, it should be fixed in efe8b91 by increasing the code block height if it's too narrow when the copy button is present, can you confirm it works for you?

[DavG25]

I've modified the behavior as changing the code block height made it seem like there were multiple lines

In the latest commit (548c3f5) the copy button should always fit inside the code block and only modify the height in edge cases

[Starlento]

I've modified the behavior as changing the code block height made it seem like there were multiple lines

In the latest commit (548c3f5) the copy button should always fit inside the code block and only modify the height in edge cases

It is perfect now.