fix(tvix/eval): address current clippy lints

Note that I've allowed `needless_lifetimes` for the attribute set
iterator, as I find the type easier to understand with these
annotations present.

Change-Id: I33abb17837ee4813076cdb9a87f54bac4a37044e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6373
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

tvix/eval/src/compiler/scope.rs

@@ -71,7 +71,7 @@ pub enum LocalPosition {
 
 /// Represents the different ways in which upvalues can be captured in
 /// closures or thunks.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum Upvalue {
     /// This upvalue captures a local from the stack.
     Local(LocalIdx),
@@ -95,7 +95,7 @@ pub enum Upvalue {
 /// is subtly different from its `StackIdx` (which excludes
 /// uninitialised values in between).
 #[repr(transparent)]
-#[derive(Clone, Copy, Debug, PartialEq, PartialOrd)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd)]
 pub struct LocalIdx(usize);
 
 /// Represents a scope known during compilation, which can be resolved