Function remove_ppa 

pub fn remove_ppa(name: &str) -> ActionSpec

Remove a PPA repository (sudo add-apt-repository -y --remove ppa:<user>/<ppa>).

Risk: Medium. Removes the apt source entry; manually reversible by running AddPpa. Requires software-properties-common to be installed.

rollback_available is false — see add_ppa’s doc for why.

name must be in <user>/<ppa> format (e.g. "deadsnakes/ppa").