docs(schema): update prefix for runtime config env variables

packages/schema/src/config/_common.ts

@@ -704,7 +704,7 @@ export default {
    * Anything under `public` and `app` will be exposed to the frontend as well.
    *
    * Values are automatically replaced by matching env variables at runtime, e.g. setting an environment
-   * variable `API_KEY=my-api-key PUBLIC_BASE_URL=/foo/` would overwrite the two values in the example below.
+   * variable `NUXT_API_KEY=my-api-key NUXT_PUBLIC_BASE_URL=/foo/` would overwrite the two values in the example below.
    *
    * @example
    * ```js
@@ -758,5 +758,5 @@ export default {
    * @type {typeof import('../src/types/config').AppConfig}
    * @version 3
    */
-   appConfig: {},
+  appConfig: {},
 }