allow Cpv type to have a slot

src/atom/mod.rs

@@ -119,6 +119,7 @@ pub struct Cpv {
     category: Category,
     name: Name,
     version: Version,
+    slot: Option<Slot>,
 }
 
 #[derive(Clone, Debug, Get, PartialEq, Eq)]
@@ -572,7 +573,13 @@ impl fmt::Display for Cp {
 
 impl fmt::Display for Cpv {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}/{}-{}", &self.category, &self.name, &self.version)
+        write!(f, "{}/{}-{}", &self.category, &self.name, &self.version)?;
+
+        if let Some(slot) = self.slot.as_ref() {
+            write!(f, ":{slot}")?;
+        }
+
+        Ok(())
     }
 }