Strategized with @balazsorban44 to open one larger PR, with changes to individual examples as separate commits.
For each example, I researched how multiple realworld codebases use the featured technology with TypeScript, to thoughtfully convert them by hand - nothing automated whatsoever.
## Documentation / Examples
- [X] Make sure the linting passes by running `pnpm lint`
- [X] The "examples guidelines" are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)
I wrote a [script](https://github.com/j0lv3r4/dependency-version-updater) to update dependencies recursively in `package.json` files, e.g.:
```
$ node index.js --path="./examples" --dependencies="react=^16.7.0,react-dom=^16.7.0"
```
This PR contains the result against the examples folder.
