Update index.mdx : "javascript" to "JavaScript" (QwikDev#6780)

Update index.mdx

packages/docs/src/routes/docs/(qwik)/components/state/index.mdx

@@ -216,7 +216,7 @@ export default component$(() => {
 });
 ```
 
-> Do you know why you should use a regular `function(){}` instead of an arrow function in `useStore()`? This is because [arrow functions don't have their own bindings to `this`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions) in javascript. This means that if you try to access `this` using an arrow function, `this.count` could point to another object's `count` 😱.
+> Do you know why you should use a regular `function(){}` instead of an arrow function in `useStore()`? This is because [arrow functions don't have their own bindings to `this`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions) in JavaScript. This means that if you try to access `this` using an arrow function, `this.count` could point to another object's `count` 😱.
 
 ## Computed state