Rollup merge of #55340 - RalfJung:operand-docs, r=oli-obk

Operands no longer appear in places

Fix an outdated comment.

src/librustc/mir/mod.rs

@@ -2065,9 +2065,8 @@ pub struct SourceScopeLocalData {
 ///////////////////////////////////////////////////////////////////////////
 // Operands
 
-/// These are values that can appear inside an rvalue (or an index
-/// place). They are intentionally limited to prevent rvalues from
-/// being nested in one another.
+/// These are values that can appear inside an rvalue. They are intentionally
+/// limited to prevent rvalues from being nested in one another.
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
 pub enum Operand<'tcx> {
     /// Copy: The value must be available for use afterwards.