docs: document parallel option on plugins (#21622)

docs/2.guide/2.directory-structure/1.plugins.md

@@ -85,6 +85,20 @@ This is useful in situations where you have a plugin that depends on another plu
 In case you're new to 'alphabetical' numbering, remember that filenames are sorted as strings, not as numeric values. For example, `10.myPlugin.ts` would come before `2.myOtherPlugin.ts`. This is why the example prefixes single digit numbers with `0`.
 ::
 
+## Loading strategy
+
+By default, Nuxt loads plugins sequentially. You can define a plugin as `parallel` so Nuxt won't wait the end of the plugin's execution before loading the next plugin.
+
+```ts
+export default defineNuxtPlugin({
+  name: 'my-plugin',
+  parallel: true,
+  async setup (nuxtApp) {
+    // the next plugin will be executed immediatly
+  }
+})
+```
+
 ## Using Composables Within Plugins
 
 You can use [composables](/docs/guide/directory-structure/composables) within Nuxt plugins: