docs: no need to register manually nitro plugin

Author: atinux

docs/content/4.api/4.advanced.md

@@ -12,24 +12,14 @@ The module adds some hooks you can use:
 
 `content:file:*` hooks are available in nitro runtime, in order to use them you need to create a custom [nitro plugin](https://nitro.unjs.io/guide/plugins.html).
 
-- Create a plugin in the `server/plugins/` directory
+Create a plugin in the `server/plugins/` directory
 
-  ```ts [server/plugins/content.ts]
-  export default defineNitroPlugin((nitroApp) => {
-    // ...
-  })
-  ```
-
-- Register the plugin in `nuxt.config.ts`
+```ts [server/plugins/content.ts]
+export default defineNitroPlugin((nitroApp) => {
+  // ...
+})
+```
 
-  ```ts [nuxt.config.ts]
-  export default defineNuxtConfig({
-    // ...
-    nitro: {
-      plugins: ['~/server/plugins/content.ts']
-    }
-  })
-  ```
 
 ### `content:file:beforeParse`
 
@@ -44,8 +34,7 @@ Arguments:
 
 ### Example
 
-Changing all occurrences of react to vue in all Markdown files:
-
+Changing all occurrences of React to Vue in all Markdown files:
 
 ```ts [server/plugins/content.ts]
 export default defineNitroPlugin((nitroApp) => {