docs: clarify async behavior and default script attributes (#390)

Author: nexoscreator

docs/content/docs/1.guides/0.key-concepts.md

@@ -39,12 +39,14 @@ to the hydration process. Instead, scripts are loaded by default when Nuxt is fu
 
 You can change this behavior by modifying the [defaultScriptOptions](/docs/api/nuxt-config#defaultscriptoptions).
 
-Nuxt Scripts will also insert several extra tags to the script element to help with performance and privacy.
+Nuxt Scripts will also insert several extra tags to the `<script>` element to optimize performance and privacy.
 - `async` - Scripts are loaded asynchronously to prevent blocking the rendering of the page.
 - `defer` - Scripts are deferred to ensure they are executed in the order they are loaded.
 - `crossorigin="anonymous"` - Scripts are loaded with the `anonymous` attribute to prevent them from accessing cookies.
 - `referrerpolicy="no-referrer"` - Scripts are loaded with the `no-referrer` policy to prevent them from sending the referrer header.
+- `fetchpriority="low"` - Scripts are loaded with lower priority to improve page performance.
 
+> **Note:** `async` is not applied by default because `defer` is used. If you need `async`, you can explicitly disable `defer`.  
 
 ## Understanding proxied functions