Documentation update

[karderio <karderio gmail com>]

Hello :o)

At the GDP we have a new contributor looking for some tasks to get him
going on documentation editing. I suggested to him that he could update
the gnome-games documentation, make it coherent across games and make it
conform to the GDP style guide.

I'm just mailing to make sure that nobody has any objections and to ask
if you might accept patches to update docs ?

Love, Karderio