Feature request: Markdown inline code syntax highlighting

[giladbarnea]

Have you searched existing Github issues to see if someone has already requested this feature?
Yes

Is your feature request related to a problem? Please describe.
I often use Heynote as a scratchpad for LLM prompts: Markdown with code blocks, sometimes in multiple languages within the same prompt. E.g.: (truncated for brevity)

**Re: 1. Referential Forks:**
I want to introduce a `StrictModel` JS class.
```js
class StrictModel {
    static fields = new Set();
    ...
}

// Usage:
...
```
And the Python equivalent:
```py
@dataclass
class StrictModel:
    ...
```

Describe the solution you'd like
Syntax highlighted code blocks, based on the language tag.

Describe alternatives you've considered
None. Heynote is awesome.

Additional context
I'll be happy to try solve this myself, unless it's surprisingly very complex for some reason.

How such Markdown looks currently in Heynote:

[abhisheksoni27]

I am working on this.

[abhisheksoni27]

is this how you envision it? @giladbarnea

[giladbarnea]

is this how you envision it? @giladbarnea

Yes absolutely! @abhisheksoni27

[abhisheksoni27]

@giladbarnea thanks! over to you @heyman #465