Mention that node can run typescript in the introduction

[..introduction.md](https://github.com/grammyjs/website/blob/main/site/docs/guide/introduction.md) states that node js cannot actually run TypeScript. Strictly speaking, [this is not true anymore](https://nodejs.org/learn/typescript/run-natively).

There are some constraints and I don't think it would be considered a good practice to do so, but it's not a "toy" feature and might be worth mentioning, maybe like

> ...Node.js can run TypeScript, although with [certain constraints](https://nodejs.org/learn/typescript/run-natively) so you might still want to go with a build step

Open site/docs/guide/introduction.md and compare the Node.js and linked Node.js TypeScript guidance. Update the introduction to acknowledge native TypeScript execution and link its constraints; done means the statement is accurate, appropriately qualified, and the documentation build passes.

Written by the indexing model from the issue text.