Fix file path reference in command to create snapper configuration

I just tried setting up a fresh install of Kali to try the new snapshotting feature and discovered a potential error in the docs. As written the command sudo cp /etc/snapper/config-templates/default /etc/snapper/configs/root will fail with the error cp: cannnot stat ‘/etc/snapper/config-templates/default’: No such file or directory on a fresh Kali 2022.1 install. I tried locate and realized there was a default snapper config file at /usr/share/snapper/config-templates/default which I believe is the one intended to be used in the documentation. This merge request fixes that path reference.