docs: add GeeksforGeeks method chaining resource with formatting fix

src/data/roadmaps/java/content/method-chaining@Ax2ouIZgN1DpPzKDy4fwp.md

@@ -4,4 +4,5 @@ Method chaining is a programming technique where multiple method calls are made
 
 Visit the following resources to learn more:
 
+- [@GeeksforGeeks@Method Chaining In Java with Examples](https://www.geeksforgeeks.org/java/method-chaining-in-java-with-examples/)
 - [@stackoverflow@How to achieve method chaining in Java](https://stackoverflow.com/questions/21180269/how-to-achieve-method-chaining-in-java)