bug#22187: 25.0.50; Synchronize TUTORIAL.it with TUTORIAL

[Eli Zaretskii]

> From: Lele Gaifax <lele@metapensiero.it>
> Date: Wed, 16 Dec 2015 21:15:55 +0100
> 
> The Italian tutorial contains several typos and lags behind the current
> English TUTORIAL.
> 
> The attached patch fixes both aspects.

Thanks, I pushed this.

Alfredo and friends, could you please review the latest version (on
the emacs-25 branch of the Emacs Git repository), and provide any
comments and changes you see fit?

Thanks.