Documentation Improvement - Include .NET 5 - Supported OS versions matrix

### Description

I'd like to suggest to improve the documentation and include the supported OS versions in the documentation page.

The matrix can be found in
- [https://github.com/dotnet/core/blob/main/release-notes/5.0/5.0-supported-os.md](https://github.com/dotnet/core/blob/main/release-notes/5.0/5.0-supported-os.md)

The following website should include the matrix
- [https://dotnet.microsoft.com/download/dotnet/5.0](https://dotnet.microsoft.com/download/dotnet/5.0)
- [https://github.com/dotnet/core](https://github.com/dotnet/core)

As an example, for this issue [https://github.com/dotnet/runtime/issues/57983](https://github.com/dotnet/runtime/issues/57983), took ages to figure out something very simple that an MS employee kindly clarified.