docs(nuxt.config): add content highlight diff lang

docs/nuxt.config.ts

@@ -62,6 +62,9 @@ export default defineNuxtConfig({
               token: process.env.NUXT_GITHUB_TOKEN || ''
             }
           : undefined
+    },
+    highlight: {
+      langs: ['bash', 'ts', 'diff', 'vue', 'json', 'yml', 'css', 'mdc']
     }
   },
   image: {