Adding --typescript option (#25831)

## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [x] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.

## Documentation / Examples

- [ ] Make sure the linting passes

Author: Abdullah Mzaien

docs/api-reference/create-next-app.md

@@ -19,6 +19,7 @@ yarn create next-app
 - **-e, --example [name]|[github-url]** - An example to bootstrap the app with. You can use an example name from the [Next.js repo](https://github.com/vercel/next.js/tree/master/examples) or a GitHub URL. The URL can use any branch and/or subdirectory.
 - **--example-path [path-to-example]** - In a rare case, your GitHub URL might contain a branch name with a slash (e.g. bug/fix-1) and the path to the example (e.g. foo/bar). In this case, you must specify the path to the example separately: `--example-path foo/bar`
 - **--use-npm** - Explicitly tell the CLI to bootstrap the app using npm. To bootstrap using yarn we recommend to run `yarn create next-app`
+- **--typescript or --ts** - Creates the default template with TypeScript instead of JavaScript.
 
 ### Why use Create Next App?