Rename @discobot's start new user command

[supermathie (Michael Brown)]

Would these links do?

• Start New User Tutorial
• Start Advanced User Tutorial

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source:

* [Start New User Tutorial](/new-message?username=discobot&title=Discobot%20Tutorial&body=@discobot%20start%20new%20user)
* [Start Advanced User Tutorial](/new-message?username=discobot&title=Discobot%20Advanced%20Tutorial&body=@discobot%20start%20advanced%20user)