Add local eslint rule to validate markdown codeblocks with React Compiler

[poteto]

In facebook/react#34462 for example, we found an issue where the compiler was incorrectly validating an example straight from the docs.

In order to find more issues like this + also provide more feedback to doc authors on valid/invalid patterns, this PR adds a new local eslint rule which validates all markdown codeblocks containing components/hooks with React Compiler. An autofixer is also provided.

To express that a codeblock has an expected error, we can use the following metadata:

// pseudo type def
type MarkdownCodeBlockMetadata = {
    expectedErrors?: {
      'react-compiler'?: number[];
    };
  };

and can be used like so:

```js {expectedErrors: {'react-compiler': [4]}}
// ❌ setState directly in render
function Component({value}) {
  const [count, setCount] = useState(0);
  setCount(value); // error on L4
  return <div>{count}</div>;
}
```

Because this is defined as a local rule, we don't have the same granular reporting that eslint-plugin-react-hooks yet. I can look into that later but for now this first PR just sets us up with something basic.

---

Stack created with Sapling. Best reviewed with ReviewStack.

• Add new eslint rule reference docs #7986
• fix compiler errors #7989
• -> Add local eslint rule to validate markdown codeblocks with React Compiler #7988

[github-actions]

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[josephsavona]

Such a great idea, love this!

[josephsavona]

Whoa, I hadn't realized how much went into this. Thank you! I scanned through, everything seems pretty reasonable. Let's ship and iterate

[poteto]

@josephsavona it was a classic case of

[josephsavona]

this is the way