Update src/routes/concepts/stores.mdx

Co-authored-by: Sarah <hello@sarahgerrard.me>

Author: thomasbuilds

src/routes/concepts/stores.mdx

@@ -270,7 +270,8 @@ setStore("users", (otherUsers) => [
 ])
 ```
 
-The path syntax appends the new element by setting it at the index equal to `store.users.length`, modifying the existing array. This triggers reactivity only for effects tracking the new index or properties like `store.users.length`, making it more efficient for targeted updates.
+The path syntax adds the new element by assigning it to the index equal to `store.users.length`, directly modifying the existing array.
+This triggers reactivity only for effects that depend on the new index or properties like `store.users.length`, making updates more efficient and targeted.
 
 ```jsx
 setStore("users", store.users.length, {