add bonus section to chapters

Author: sumn2u

en/SUMMARY.md

@@ -135,17 +135,17 @@
   - [Arrow Functions](es6-concepts/arrow-functions.md)
   - [Destructuring](es6-concepts/destructuring.md)
   - [Template Literals](es6-concepts/template-literals.md)
-- [Animation Resources](animation-resources/README.md)
+- [Animation Resources (Bonus Section)](animation-resources/README.md)
   - [GSAP](animation-resources/gsap.md)
   - [Anime JS](animation-resources/animejs.md)
   - [Three JS](animation-resources/threejs.md)
   - [Velocity JS](animation-resources/velocityjs.md)
   - [React Spring](animation-resources/react-spring.md)
   - [Framer Motion](animation-resources/framer-motion.md)
-- [Complexity](complexity/README.md)
+- [Complexity (Bonus Section)](complexity/README.md)
   - [Space Complexity](complexity/space-complexity.md)
   - [Time Complexity](complexity/time-complexity.md)
-- [JavaScript Behind the Scenes](behind-scenes/README.md)
+- [JavaScript Behind the Scenes (Bonus Section)](behind-scenes/README.md)
   - [Call Stack](behind-scenes/call-stack.md)
   - [JavaScript Engine](behind-scenes/engine.md)
   - [Event Loop](behind-scenes/event-loop.md)