Welcome message minor change

[FedeLopez17]

This change rephrases the bot's welcome message so that it grabs newcomers' attention a bit more.

[cubiquitous]

I'm ok approving this review, but why you keep using \n instead of just breaking the line?!

edit: when using backticks it allows and takes in consideration all spaces. so:

`hey\nguys`

is the same as

`hey
guys`