Apply suggestion from @Copilot

sumn2u · Copilot · sumn2u · commit 9d6719b7102b · 2025-12-01T07:27:53.000-05:00
Co-authored-by: Copilot &lt;175728472+Copilot@users.noreply.github.com&gt;
diff --git a/cn/strings/substring.md b/cn/strings/substring.md
@@ -33,7 +33,7 @@ console.log(result);
 
 
 // 输出
-for
+Geeks
 ```
 
 ```javascript
