Example of "All members must conform to the string index signature" looks wrong to me

https://basarat.gitbook.io/typescript/type-system/index-signatures#all-members-must-conform-to-the-string-index-signature

```
/** Error */
interface Bar {
x: number;
y: string; // ERROR: Property `y` must be of type number
}
```

Actually this example is not error

Open the linked TypeScript Book section, “All members must conform to the string index signature,” and verify the reported interface example against TypeScript’s behavior. Update the example or explanation so it accurately reflects whether the mixed property types produce an error, then confirm the rendered section is correct.

Written by the indexing model from the issue text.