doc: sack: warning about using excludes, includes, disabling and enabling repos
doc: sack: warning about using excludes, includes, disabling and enabling repos

Conan-Kudo/hawkey,rholy/hawkey,mizdebsk/hawkey,megaumi/hawkey,ignatenkobrain/hawkey,ignatenkobrain/hawkey,mizdebsk/hawkey,mluscon/hawkey,mizdebsk/hawkey,rpm-software-management/hawkey,mluscon/hawkey,rpm-software-management/hawkey,Conan-Kudo/hawkey,Conan-Kudo/hawkey,ignatenkobrain/hawkey,mluscon/hawkey,ignatenkobrain/hawkey,megaumi/hawkey,rpm-software-management/hawkey,megaumi/hawkey,rholy/hawkey,mluscon/hawkey,rholy/hawkey,megaumi/hawkey,mizdebsk/hawkey,rpm-software-management/hawkey,Conan-Kudo/hawkey,rholy/hawkey