Better rendering of front-end chat: resolve overflow issue and add syntax highlighting

[xingyaoww]

What problem or use case are you trying to solve?

Markdown is NOT rendered properly while the animation of generation is happening.

When generation is completed, the code block is properly displayed:

Describe the UX of the solution you'd like

But:

• The chat bubble somehow overflowed. Is there a way that we make the code block horizontally scrollable rather than make the entire chat window have a horizontal scroll bar (like in the screenshot)?
• It would be nice if we could add automatic syntax highlights to those code blocks.

Do you have thoughts on the technical implementation?

Describe alternatives you've considered

Additional context

[amanape]

All the issues addressed here have been solved with the #1402 ad #1488 PRs. Should have closed