fix typo in operator.rs

Author: RalfJung

src/tools/miri/src/operator.rs

@@ -24,7 +24,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
 
         Ok(match bin_op {
             Eq | Ne | Lt | Le | Gt | Ge => {
-                assert_eq!(left.layout.abi, right.layout.abi); // types an differ, e.g. fn ptrs with different `for`
+                assert_eq!(left.layout.abi, right.layout.abi); // types can differ, e.g. fn ptrs with different `for`
                 let size = this.pointer_size();
                 // Just compare the bits. ScalarPairs are compared lexicographically.
                 // We thus always compare pairs and simply fill scalars up with 0.