docs: update runtimeConfig example

Author: danielroe

docs/pages/en/1.getting-started/2.configuration.md

@@ -39,9 +39,9 @@ import { defineNuxtConfig } from 'nuxt'
 
 export default defineNuxtConfig({
   modules: ['@nuxtjs/sanity'],
-  privateRuntimeConfig: {
+  runtimeConfig: {
     sanity: {
-      token: process.env.SANITY_TOKEN,
+      token: process.env.NUXT_SANITY_TOKEN,
     },
   },
   sanity: {