message: docs: update ivy opt-in flag
  Followup to and
  Note: this flag will only work on `@angular/cli@8.0.0-beta.3` (currently unreleased) and above.
  PR Close
diff: ## Starting a new project using Ivy
  -To start a new project with Ivy enabled, use the `--experimental-ivy` flag with the [`ng new`](cli/new) command:
  +To start a new project with Ivy enabled, use the `--enable-ivy` flag with the [`ng new`](cli/new) command:
  ```sh
  -ng new shiny-ivy-app --experimental-ivy
  +ng new shiny-ivy-app --enable-ivy
  ```
  Everything will be configured for you:
  