fix minor stuff

src/backend/actual/rust.rs

@@ -37,8 +37,8 @@ impl Backend for Rust {
             .context("getting all installed packages")
     }
 
-    fn make_dependency(&self, packages: &[Package]) -> Result<ExitStatus> {
-        unreachable!()
+    fn make_dependency(&self, _: &[Package]) -> Result<ExitStatus> {
+        unreachable!("cargo does not have unmanaged packages")
     }
 }
 

src/backend/backend_trait.rs

@@ -32,6 +32,7 @@ pub(crate) trait Backend: Debug {
     /// Get all packages that were installed in the system explicitly.
     fn get_explicitly_installed_packages(&self) -> Result<HashSet<Package>>;
 
+    // TODO continue here
     fn assign_group(&self, to_assign: Vec<(Package, Rc<Group>)>) {
         todo!();
         let mut group_package_map = HashMap::new();