Small updates to twilio docs

[cjavdev]

• Moves the required option to the top to make it more clear that the message param is required. Starting with the optional params threw me off and I'm not sure everyone will read all the way to the bottom.
• Updates the has for the format_for_twilio thing to make it a little easier to copy/paste as it matches the default creds.

[excid3]

Thanks @cjavdev!