Update styling of the JavaScript Behind the Scenes in SUMMARY.md

Author: sumn2u

en/SUMMARY.md

@@ -133,10 +133,10 @@
   - [Velocity JS](animation-resources/velocityjs.md)
   - [React Spring](animation-resources/react-spring.md)
   - [Framer Motion](animation-resources/framer-motion.md)
-- [JavaScript behind the scenes](behind-scenes/README.md)
-  - [Call stack](behind-scenes/call-stack.md)
+- [JavaScript Behind the Scenes](behind-scenes/README.md)
+  - [Call Stack](behind-scenes/call-stack.md)
   - [Engine](behind-scenes/engine.md)
-  - [Event loop](behind-scenes/event-loop.md)
+  - [Event Loop](behind-scenes/event-loop.md)
 - [References](References.md)
 - [Resources](resources.md)
 - [Credits](Credits.md)