fix the debian instructions
* "basé" is anglicism (on based) for the french word "fondé" * `apt-get` comes from the old apt tools. is not aptitude. if you have aptitude installed on your system, then you know why you installed it and you probably don't need those instructions. so the recommended way for newbies to install a package is `apt` nowadays. * guile 3 is only available on testing/unstable versions of debian. if you really want guile 3 on it, i really recommand to use debootstrap and chroot.