[Doc] Update Next.js + Static Web Apps

[Reshmi-Sriram]

Update to reflect the latest addition of Hybrid (Static + SSR) Next.js support in Azure Static Web Apps. For more information kindly refer to https://aka.ms/swanextjsssr

Bug

• [ ] Related issues linked using fixes #number
• [ ] Integration tests added
• [ ] Errors have a helpful link attached, see contributing.md

Feature

• [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
• [ ] Related issues linked using fixes #number
• [ ] Integration tests added
• [ ] Documentation added
• [ ] Telemetry added. In case of a feature if it's used or not.
• [ ] Errors have a helpful link attached, see contributing.md

Documentation / Examples

• [ ] Make sure the linting passes by running pnpm lint
• [ ] The "examples guidelines" are followed from our contributing doc