Update other doc.

Value was renamed to Operand in ad2de8b
ScalarPair to Slice in fe50b4e

Not familiar enough with rustc's source to know if the comment is even still applicable.

Author: goddessfreya

src/librustc/mir/interpret/value.rs

@@ -17,8 +17,8 @@ pub struct RawConst<'tcx> {
     pub ty: Ty<'tcx>,
 }
 
-/// Represents a constant value in Rust. `Scalar` and `ScalarPair` are optimizations that
-/// match the `LocalState` optimizations for easy conversions between `Value` and `ConstValue`.
+/// Represents a constant value in Rust. `Scalar` and `Slice` are optimizations that
+/// match the `LocalState` optimizations for easy conversions between `Operand` and `ConstValue`.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord,
          RustcEncodable, RustcDecodable, Hash, HashStable)]
 pub enum ConstValue<'tcx> {