review: replace i32 with Vec<i32> as roll return type for future exploding dice

01.workspace/oxidice_lib/src/imp/handful_roll.rs

@@ -4,7 +4,7 @@ impl Handful {
     pub fn roll(self) -> Outcome {
         let mut die_rolls = Vec::<i32>::new();
         for die in self.dice {
-            die_rolls.push(die.roll());
+            die_rolls.append(&mut die.roll());
         }
         Outcome::List(die_rolls)
     }