consider adding file watcher to `sync-docs` command

This might be controversial, so feel free to close.

I'm currently running the `sync-docs` command inside a file watcher for ease of use. Either add directly to the script or as separate command.
This is what I'm currently running:
```
npx chokidar-cli "../../../svelte-cli/**/*.md" -c "pnpm sync-docs"
```