docs: fix cli param

[ananni13]

--init is not a valid option for create-remix.

Launching the script as it is now, the CLI will pick up --init as the folder name to use to create the project, and won't ask for one.

If the intention was to automatically launch the remix.init script, we should use --init-script instead.

Test Plan

Checklist

- [ ] Tests updated

• Docs updated

[kentcdodds]

Thank you!