Adding nextjs starting example

Editor assessment

The subject states the addition: a Next.js starting example was added to the installation docs. The installation scope is a proper docs-section noun, the docs type matches, and both the framework and the deliverable are named, so the reader knows exactly what was added and where. There is no body, acceptable for a small example addition whose headline is complete. No footers appear. The gerund adding departs from imperative mood, a minor note. The message is clear, targeted, and self-sufficient for its size.