Update Homework 2 title to Fall 2025

Author: LuYifan00

_toc.yml

@@ -62,7 +62,7 @@ parts:
   - file: chapters/homework/homework1-solution
     title: Homework 1 Solution (Fall 2025)
   - file: chapters/homework/homework2
-    title: Homework 2 (Fall 2024)
+    title: Homework 2 (Fall 2025)
 - caption: Course Project
   chapters:
   - file: chapters/project/FinalProject-2025Fall