Fix example in rationale.md (#19889)

docs/rationale.md

@@ -35,10 +35,11 @@ You can disable this conditional behavior with the [`objectWrap`](options.md#obj
 
 **Tip:** If you have a multi-line object that you’d like to join up into a single line:
 
+<!-- prettier-ignore -->
 ```js
 const user = {
   name: "John Doe",
-  age: 30,
+  age: 30
 };
 ```
 

website/versioned_docs/version-stable/rationale.md

@@ -35,10 +35,11 @@ You can disable this conditional behavior with the [`objectWrap`](options.md#obj
 
 **Tip:** If you have a multi-line object that you’d like to join up into a single line:
 
+<!-- prettier-ignore -->
 ```js
 const user = {
   name: "John Doe",
-  age: 30,
+  age: 30
 };
 ```