docs: change for generating page title in default.vue

[AndreasMueck]

❓ Type of change

• [x] 📖 Documentation (updates to the documentation, readme or JSdoc annotations)
• [ ] 🐞 Bug fix (a non-breaking change that fixes an issue)
• [ ] 👌 Enhancement (improving an existing functionality like performance)
• [ ] ✨ New feature (a non-breaking change that adds functionality)
• [ ] 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• [ ] ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

Change in the Nuxt SEO docs. With the method described it was not possible to set the page title from definePageMeta as the default title.