Emacsclient compatible key binding

[jidanni]

Many users are used to Emacsclient C-x # to end an edit.

But if we rebind your C-c C-c to that, maybe it will cause some problem. Especially when we see the documentation to server-edit (C-h k C-x #).

So maybe your documentation should say what those people should do to keep their emacsclient habit.