Add sudo to install instructions so it can be run without user switching

[Sleuth56]

Currently you have to either su to root to run pacman or manually prepend sudo to it. This fixes that. Because makepkg doesn't let you run as root su-ing to root doesn't work so sudo-ing the pacman command makes it easier for a normal user.

[Jguer]

@Sleuth56 can you make the same change to the chain command and add the disclaimer before to switch sudo to the user's preferred alternative such as run0 or doas?