chore(readme): add link to collections fastutil

vectrixdevelops · vectrixdevelops · commit dfe47cca67a4 · 2025-10-27T15:27:45.000+13:00
diff --git a/readme.md b/readme.md
@@ -16,6 +16,7 @@
 Provides thread-safe utilities for highly concurrent scenarios in Java.
 
 * [Sync Collections](collections/readme.md)
+* [Sync Collections `fastutil`](collections-fastutil/readme.md)
 
 ## Building
 
