Find or write mdbook plugin to have code blocks in tables

## Problem

Neither Markdown dialect seems to support fenced code blocks in tables.
Something like this (here HTML):

GDScript
Rust

class_name MyClass

extends Node

        

#[derive(GodotClass)]

#[class(base=Node)]

struct MyClass;

In mdbook, it's possible to use raw HTML, but it's also very unreadable.
This is the source for the above. Yes, the line breaks need to be like that to avoid trailing/leading empty lines.

```html

GDScript
Rust

class_name MyClass

extends Node

        

#[derive(GodotClass)]

#[class(base=Node)]

struct MyClass;

```

## Possible solutions

With mdbook, the tag `` can be used for syntax highlighting instead of `

`.


We should research if there is an mdbook plugin achieving something similar, or write our own.

If we do it ourselves, it doesn't necessarily need to be generic and reusable. We could just start to support the above case and take it from there. Even something simple such as

```codetable left="gdscript" right="rust"

class_name MyClass

extends Node

---

#[derive(GodotClass)]

#[class(base=Node)]

struct MyClass;

```



could be transformed into the verbose HTML above.

Start by researching whether an mdBook plugin already supports fenced code blocks inside tables, using the raw HTML example and proposed `codetable` syntax in this issue as requirements. If no suitable plugin exists, define how the compact syntax should become readable HTML with syntax-highlighted Rust and GDScript blocks, then verify the rendered documentation output.

Written by the indexing model from the issue text.