doc: avoid proposal syntax in code example

PR-URL: #30685
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Myles Borins <myles.borins@gmail.com>

doc/api/esm.md

@@ -667,7 +667,10 @@ CommonJS and ES module instances of the package:
 
     ```js
     // ./node_modules/pkg/index.mjs
-    export state from './state.cjs';
+    import state from './state.cjs';
+    export {
+      state
+    };
     ```
 
    Even if `pkg` is used via both `require` and `import` in an application (for