Edit dialogs in sandbox for tutorial fr

[m2gi-glembaa]

The first time I used the app, I didn't know that "Learn Git Branching" offered commands to improve the user experience, for example I didn't know how to go back to the menu with all the levels once my first level was finished.

Before :

After :

Also, the "checkout" command is deprecated, it might be good to inform users about it

New :

And the title "Sharing is caring!" can be improved

Before :

After :

I have already made the necessary modifications to these issues

[m2gi-glembaa]

I have added some images to compare the before and after in the interface

[pcottle]

I'm supportive of these updates! Do you have a PR?