Highlight @example jsdoc body as source code

TS and JS Grammar Extension version: 0.0.47 / latest

Code
For a js doc body such as:

/**
 * @example
 * 1 + 1
 */
const a = 1

We mark the body of the @example block specially but do not actually syntax highlight it. I added an injection grammar in VS Code that does this: https://github.com/Microsoft/vscode/blob/master/extensions/typescript-basics/syntaxes/ExampleJsDoc.injection.tmLanguage.json

May be worth including in the core grammar. Let me know if you agree. The injection grammar will not work as is, we're relying on another injection grammar that handles separating the leading stars of the doc block from the documentation content itself

Examinez le fichier lié VS Code ExampleJsDoc.injection.tmLanguage.json et la gestion de la grammaire TypeScript/JavaScript du dépôt pour les commentaires JSDoc. Confirmez comment l'injection existante sépare les astérisques initiaux du contenu de la documentation ; le travail est considéré comme terminé lorsque le corps d'un bloc @example reçoit une coloration syntaxique du code source.