refactor(tvix/eval): implement IntoIterator for NixList

This is the same code as before, just moved into a trait impl to gain
access to stuff that needs IntoIterator

Change-Id: Iff9375cd05593dd2681fa85ccc7f4554bf944a02
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6842
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

tvix/eval/src/value/list.rs

@@ -79,10 +79,6 @@ impl NixList {
         self.0.iter()
     }
 
-    pub fn into_iter(self) -> std::vec::IntoIter<Value> {
-        self.0.into_iter()
-    }
-
     /// Compare `self` against `other` for equality using Nix equality semantics
     pub fn nix_eq(&self, other: &Self, vm: &mut VM) -> Result<bool, ErrorKind> {
         if self.len() != other.len() {
@@ -98,3 +94,12 @@ impl NixList {
         Ok(true)
     }
 }
+
+impl IntoIterator for NixList {
+    type Item = Value;
+    type IntoIter = std::vec::IntoIter<Value>;
+
+    fn into_iter(self) -> std::vec::IntoIter<Value> {
+        self.0.into_iter()
+    }
+}