Update NuGet metadata to point to fsprojects docs and surface documentation links

[Copilot]

NuGet package metadata currently points to an outdated project URL and does not expose enough documentation entry points. This PR updates package metadata so the NuGet page links to the fsprojects site and includes direct docs links in the package description.

• Metadata link correction

  • Updated projectUrl in src/Zander/paket.template from the legacy repository URL to the fsprojects documentation site:
    • https://fsprojects.github.io/Zander/

• NuGet description enrichment

  • Extended the package description to include direct links for:
    • main documentation
    • tutorial
    • API reference
    • source repository

Example of the updated metadata block:

description
    ...
    Documentation: https://fsprojects.github.io/Zander/
    Tutorial: https://fsprojects.github.io/Zander/tutorial.html
    API Reference: https://fsprojects.github.io/Zander/reference/index.html
    Source: https://github.com/fsprojects/Zander
projectUrl
    https://fsprojects.github.io/Zander/

[wallymathieu]

There is no site https://fsprojects.github.io/Zander/ @copilot