fix: Update examples removing unused index

Author: erasmoh

src/content/learn/choosing-the-state-structure.md

@@ -460,7 +460,7 @@ export default function Menu() {
     <>
       <h2>What's your travel snack?</h2> 
       <ul>
-        {items.map((item, index) => (
+        {items.map((item) => (
           <li key={item.id}>
             <input
               value={item.title}
@@ -527,7 +527,7 @@ export default function Menu() {
     <>
       <h2>What's your travel snack?</h2>
       <ul>
-        {items.map((item, index) => (
+        {items.map((item) => (
           <li key={item.id}>
             <input
               value={item.title}