use <script> and <style> for script and style instead of unique markdown blocks

[swyxio]

as i explore this space more i think the ideal authoring experience really looks something like this:

---
title: foo
bar: baz
---

<script>
import Counter from './path/to/Counter.svelte';
import {H1, UL, LI} from './customComponents.svelte';

let number = 500;
export let mdsvexComponents = {H1, UL, LI}
</script>

<style>
	ul {
		color: red
	}
</style>

<script module>
export let potato = "russet"
</script>

# hi! this is markdown in svelte!

<Counter count="{number}" />

Inline components <Counter count="{5}" /> are absolute fine too.

I like lists:

- these are rendered
- with custom svelte
- components

\```js
const str = `this just displays as a normal code block`
\```

so working backwards from the ideal experience we could explore being a loader fork instead of being a svelte preprocessor?

[louwers]

Why not write a pandoc filter instead of implementing a shabby parser in Javascript/Typescript?

[pngwn]

There are a number of reasons but pandoc was never an option.

[pngwn]

This is done in 0.8.