Improve comment phrasing

Co-authored-by: oliver <[email protected]>

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -763,7 +763,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     {
                         if steps > 0 {
                             // Don't care about `&mut` because `DerefMut` is used less
-                            // often and user will not expect autoderef happens.
+                            // often and user will not expect that an autoderef happens.
                             if let Some(hir::Node::Expr(hir::Expr {
                                 kind:
                                     hir::ExprKind::AddrOf(