Fix small typo

transmutting -> transmuting

compiler/rustc_passes/src/intrinsicck.rs

@@ -78,7 +78,7 @@ fn check_transmute(&self, span: Span, from: Ty<'tcx>, to: Ty<'tcx>) {
                 return;
             }
 
-            // Special-case transmutting from `typeof(function)` and
+            // Special-case transmuting from `typeof(function)` and
             // `Option<typeof(function)>` to present a clearer error.
             let from = unpack_option_like(self.tcx, from);
             if let (&ty::FnDef(..), SizeSkeleton::Known(size_to)) = (from.kind(), sk_to) {